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Onyx Boox Tab Ultra C Review | 68 Data compared

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  • Avg. price in UK: ~£570
  • Avg. price in US: ~$600
  • Screen size: 10.3 inches
  • Battery life: 20 hours
  • Supported bookstore ecosystem: Android Open Ecosystem

Onyx Boox Tab Ultra C review. Compare 68 technical specifications and user reviews to see how it ranks among ereaders and if it is worth buying.

8.4

Overall score

What it is: An overall evaluation of the eReader's quality, based on technical analyses and user reviews.

When it matters: When you need a quick reference to identify the best eReaders on the market.

Score components:

90.0%

8.5

Technical Score

10.0%

7.4

User score

Excellent
8.5

Technical Score

What it is: An assessment of the eReader's technical performance, covering key areas such as display quality, reading features, battery life, format support, ecosystem, and design.

When it matters: When you want to compare eReaders based on technical performance and available features.

Score components:

25.0%

9.7

Display

22.0%

9.9

Reading

18.0%

6.7

Battery

14.0%

9.6

Hardware

12.0%

8.7

Connectivity

9.0%

3.0

Design

Excellent
7.4

User score

What it is: A rating that combines user reviews and the total number of reviews received by the eReader.

When it matters: When you want to know how an eReader feels in daily reading and how reliable it is for screen comfort, battery life, and library management according to user feedback.

Score components:

70.0%

7.6

User reviews

30.0%

7.1

Popularity

User score:
United States
Amazon_logo.png
3.7
(144)
United Kingdom
amazon
3.7
(133)
amazon
3.9
(132)
amazon
3.7
(21)

(Reviews last updated: Apr 2026)

Very good
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    Best prices in UK

    Best rankings

    ?

    Available: ranking among products currently available (including other versions of this product).
    All: ranking among all products in the database.

    Verdict

    The Onyx Boox Tab Ultra C is a high-performance 10.3-inch color e-reader featuring an E Ink Kaleido 3 display that offers 300 ppi for black-and-white and 150 ppi for color content. Under the hood, it is powered by a Qualcomm octa-core processor paired with 4GB of RAM and 128GB of internal storage, expandable via a microSD slot up to 2TB. Main characteristics include a 16MP rear camera for document scanning, a 6,300mAh battery for extended use, and an Android 11 operating system that provides full access to the Google Play Store. Its primary pros are the eye-friendly color e-paper experience, a highly responsive Wacom layer for 4,096 levels of stylus pressure sensitivity, and a dedicated GPU for smoother page refreshes. However, users should note cons such as muted color vibrancy compared to traditional tablets, a relatively heavy 480g build that may hinder one-handed use, and the absence of a 3.5mm headphone jack or physical volume buttons.

    Technical Specifications of eReader Onyx Boox Tab Ultra C

    Technical Score

    What it is: An assessment of the eReader's technical performance, covering key areas such as display quality, reading features, battery life, format support, ecosystem, and design.

    When it matters: When you want to compare eReaders based on technical performance and available features.

    Score components:

    25.0%

    9.7

    Display

    22.0%

    9.9

    Reading

    18.0%

    6.7

    Battery

    14.0%

    9.6

    Hardware

    12.0%

    8.7

    Connectivity

    9.0%

    3.0

    Design

    8.5
    Onyx Boox Tab Ultra C has a technical score of 8.47 points, which is higher than that of 96.7% of products in this category.
    User score

    What it is: A rating that combines user reviews and the total number of reviews received by the eReader.

    When it matters: When you want to know how an eReader feels in daily reading and how reliable it is for screen comfort, battery life, and library management according to user feedback.

    Score components:

    70.0%

    7.6

    User reviews

    30.0%

    7.1

    Popularity

    User score:
    United States
    Amazon_logo.png
    3.7
    (144)
    United Kingdom
    amazon
    3.7
    (133)
    amazon
    3.9
    (132)
    amazon
    3.7
    (21)

    (Reviews last updated: Apr 2026)

    7.4
    Onyx Boox Tab Ultra C has a user score of 7.43 points, which is lower than that of 74.6% of products in this category.
    Popularity
    What it is: An indicator based on the number of reviews received by the eReader.
    When it matters: When you prefer to choose an eReader reviewed and selected by many other buyers.
    7.1
    Onyx Boox Tab Ultra C has a popularity of 7.1 points, which is higher than 62.3% of smartphones.
    Ratio quality/price

    What it is: An indicator that combines the eReader's overall rating with its cost.

    When it matters: When you are looking for an eReader with a good balance between reading comfort, features, and price.

    Score components:

    60.0%

    8.4

    Overall score

    40.0%

    7.5

    Price

    8.1
    Onyx Boox Tab Ultra C has a quality-to-price ratio of 8.1 points, which is higher than 73% of smartphones.
    Brand name
    What it is: Identifies the company or ecosystem behind the device, which often shapes the store, software approach, and accessory support.
    When it matters: When you are choosing between Kindle, Kobo, Boox, PocketBook, or another ecosystem with different store access and software behavior.

    Importance: MEDIUM

    Onyx
    Screen size
    What it is: The diagonal measurement of the reading panel, usually given in inches.
    When it matters: When you are deciding between a small travel reader and a larger page that works better for PDFs, comics, or textbooks.

    Importance: HIGH

    Good value: >=7.8

    10.3 inches
    Onyx Boox Tab Ultra C has a screen size of 10.3 inches which is larger than 86.9% of eReaders on this spec and equal to 11.5% of eReaders.
    Screen resolution
    What it is: The total pixel grid shown on the panel, normally written as width by height.
    When it matters: When small fonts, diagrams, or dense page layouts need to stay readable without constant zooming.

    Importance: HIGH

    1860x2480 px
    Onyx Boox Tab Ultra C uses a screen resolution of 1860x2480 px, which is sharper than that of 95.1% of eReaders and the same as that of 4.9% of eReaders.
    Pixel density
    What it is: The number of pixels packed into each inch of the display, expressed in ppi.
    When it matters: When you want text edges to look cleaner and serif fonts to resemble print more closely.

    Importance: HIGH

    Good value: >=300

    300 ppi
    Onyx Boox Tab Ultra C has a pixel density of 300 ppi which is higher than 51.6% of eReaders on this spec and equal to 48.4% of eReaders.
    150 ppi in color.
    E-paper display
    What it is: Uses an electrophoretic panel designed to mimic paper rather than a conventional backlit phone or tablet screen.
    When it matters: When you read for long stretches and want lower glare and less screen-like fatigue than on LCD or OLED devices.

    Importance: LOW

    yes
    Onyx Boox Tab Ultra C uses an e-paper display. 97.6% of eReaders have an e-paper display.
    Show more
    Supported file types
    What it is: Lists which ebook, document, image, or audio formats the reader can open without conversion.
    When it matters: When your library comes from mixed sources instead of one locked bookstore.

    Importance: HIGH

    24
    Onyx Boox Tab Ultra C supports 24 file types which is more than 84% of eReaders on this spec and equal to 6% of eReaders.
    PDF reflow support
    What it is: Can rearrange PDF text into a more readable, screen-sized layout instead of forcing the original fixed page.
    When it matters: When you read A4 documents, articles, or manuals on a smaller eReader screen.

    Importance: HIGH

    yes
    Onyx Boox Tab Ultra C offers PDF reflow. 55.4% of eReaders support PDF reflow.
    Annotation support
    What it is: Allows highlighting, handwritten notes, typed comments, or markup directly inside supported files.
    When it matters: When you study, review academic papers, or want your notes to stay attached to the exact passage.

    Importance: HIGH

    yes
    Onyx Boox Tab Ultra C offers annotation support. 100% of eReaders offer annotation support.
    Dictionary
    What it is: Provides built-in word lookup while you read.
    When it matters: When you read in another language or want quick definitions without leaving the page.

    Importance: MEDIUM

    yes
    Onyx Boox Tab Ultra C includes a built-in dictionary. 99.2% of eReaders include a built-in dictionary.
    Text-to-speech
    What it is: Converts on-screen text into spoken audio using a synthetic voice.
    When it matters: When you want to keep following a book while resting your eyes, walking, or multitasking.

    Importance: MEDIUM

    yes
    Onyx Boox Tab Ultra C offers text-to-speech. 64.2% of eReaders include text-to-speech.
    Show more
    Battery life
    What it is: Estimates how long the device can keep running between charges under normal reading conditions.
    When it matters: When you travel, commute, or want to finish books for days without thinking about charging.

    Importance: HIGH

    Good value: >=30

    20 hours
    Onyx Boox Tab Ultra C offers 20 hours of battery life which is shorter than 61.3% of eReaders on this spec and equal to 12.5% of eReaders.
    highly variable, around 14h with 100% frontlight, but can last multiple days with typical usage
    Battery capacity
    What it is: The amount of energy the battery can store, commonly expressed in mAh.
    When it matters: When you want a rough hardware indicator of how much power reserve the device has.

    Importance: MEDIUM

    Good value: >=2000

    6,300 mAh
    Onyx Boox Tab Ultra C has a battery capacity of 6300 mAh which is higher than 98.3% of eReaders on this spec and equal to 1.7% of eReaders.
    Charging time
    What it is: The approximate time needed to recharge the battery from low to full.
    When it matters: When you often top up shortly before leaving and need the reader ready again quickly.

    Importance: MEDIUM

    Good value: <=3

    2 hours
    Onyx Boox Tab Ultra C takes 2 hours to charge which is quicker than 49% of eReaders on this spec and equal to 40.4% of eReaders.
    Varies depending on charger used; reports range from around 2 hours with fast charging to over 4.5 hours with a 9W adapter
    Wireless charging
    What it is: Can recharge on a compatible charging pad without plugging in a cable.
    When it matters: When you prefer drop-and-charge convenience on a desk or bedside stand.

    Importance: LOW

    no
    Onyx Boox Tab Ultra C does not offer wireless charging. 7.3% of eReaders offer wireless charging.
    Internal storage
    What it is: The built-in space available for books, notes, audiobooks, apps, and downloaded documents.
    When it matters: When you keep large libraries offline or store a lot of PDFs and audio locally.

    Importance: HIGH

    Good value: >=32

    128 GB
    Onyx Boox Tab Ultra C offers 128 GB of internal storage which is more than 94.1% of eReaders on this spec and equal to 5.9% of eReaders.
    RAM capacity
    What it is: The amount of working memory used for page rendering, multitasking, and keeping content active in the background.
    When it matters: When you open heavy files, switch between books, or expect the interface to stay snappy.

    Importance: MEDIUM

    Good value: >=2

    4 GB
    Onyx Boox Tab Ultra C offers 4 GB of RAM which is more than 86.6% of eReaders on this spec and equal to 10.1% of eReaders.
    CPU base clock speed
    What it is: The baseline operating frequency of the main processor under normal load.
    When it matters: When you compare readers for faster menu navigation, indexing, and handling of larger documents.

    Importance: MEDIUM

    8 x 2 GHz
    Onyx Boox Tab Ultra C has a CPU base clock speed of 8 x 2 GHz, which is faster than that of 82.6% of eReaders and the same as that of 12.4% of eReaders.
    Operating system
    What it is: The software platform that drives the interface, reading apps, and deeper system capabilities.
    When it matters: When you care about app availability, customization, and how flexible the device can become beyond basic reading.

    Importance: HIGH

    Android 11
    Onyx Boox Tab Ultra C runs Android 11, which is more advanced than that of 76.2% of eReaders and the same as that of 17.2% of eReaders.
    Android 11
    Memory card slot
    What it is: Accepts removable storage so the library can expand beyond the built-in capacity.
    When it matters: When your collection will outgrow internal storage or you move files between devices manually.

    Importance: MEDIUM

    yes
    Onyx Boox Tab Ultra C has a memory card slot. 43.1% of eReaders have a memory card slot.
    Show more
    Wi-Fi connectivity
    What it is: Connects the reader to wireless networks for book downloads, syncing, updates, and online services.
    When it matters: When you buy books directly on the device or keep your library synced without using a cable.

    Importance: HIGH

    yes
    Onyx Boox Tab Ultra C connects over Wi-Fi. 93.5% of eReaders have Wi-Fi.
    Wi-Fi version
    What it is: Specifies which wireless networking standard is supported, such as Wi-Fi 4, 5, or 6.
    When it matters: When router compatibility, wireless stability, or faster transfers on newer home networks matter to you.

    Importance: LOW

    Wi-Fi 5 (802.11ac), Wi-Fi 4 (802.11n)
    Onyx Boox Tab Ultra C supports Wi-Fi Wi-Fi 5 (802.11ac), Wi-Fi 4 (802.11n), which is newer than that of 58.2% of eReaders and the same as that of 40.2% of eReaders.
    Wi-Fi bands supported
    What it is: Shows whether the reader can use 2.4 GHz, 5 GHz, or both wireless bands.
    When it matters: When crowded apartment Wi-Fi or 5 GHz-only setups make band support matter at home or in the office.

    Importance: LOW

    2.4 GHz+5 GHz
    Onyx Boox Tab Ultra C supports 2.4 GHz+5 GHz Wi-Fi bands, which is broader than that of 57.4% of eReaders and the same as that of 42.6% of eReaders.
    Bluetooth
    What it is: Provides short-range wireless pairing for headphones, speakers, keyboards, page turners, or other accessories.
    When it matters: When you listen to audiobooks, use a remote page turner, or want cable-free accessories around the house.

    Importance: MEDIUM

    yes
    Onyx Boox Tab Ultra C connects over Bluetooth. 60.2% of eReaders have Bluetooth.
    Bluetooth version
    What it is: Identifies the supported Bluetooth generation, which affects efficiency, codec support, and compatibility.
    When it matters: When you pair newer headphones and want a more stable, lower-power wireless connection.

    Importance: LOW

    Good value: >=5.0

    5.0
    Onyx Boox Tab Ultra C supports Bluetooth 5.0 which is newer than 58.5% of eReaders on this spec and equal to 28.8% of eReaders.
    Show more
    Weight
    What it is: The mass of the device, usually measured in grams.
    When it matters: When one-handed comfort matters and you do not want the reader to feel tiring during long sessions.

    Importance: HIGH

    Good value: <=200

    480 g
    Onyx Boox Tab Ultra C weighs 480 g which is heavier than 90.2% of eReaders on this spec and equal to 0.8% of eReaders.
    Thickness
    What it is: The depth of the body from front to back, usually measured in millimetres.
    When it matters: When grip comfort, sleeve fit, or how slim the reader feels in the hand matters to you.

    Importance: MEDIUM

    Good value: <=8

    6.7 mm
    Onyx Boox Tab Ultra C is 6.7 mm thick which is thinner than 82.5% of eReaders on this spec and equal to 0.8% of eReaders.
    Height
    What it is: The vertical size of the body, usually measured from top to bottom in millimetres.
    When it matters: When you are checking whether the reader will fit a bag, jacket pocket, or small stand.

    Importance: LOW

    Good value: <=160

    225 mm
    Onyx Boox Tab Ultra C is 225 mm tall which is taller than 77.1% of eReaders on this spec and equal to 0.8% of eReaders.
    Width
    What it is: The side-to-side body measurement, usually given in millimetres.
    When it matters: When one-handed reach and how much space the reader takes in a bag or bedside setup matter.

    Importance: LOW

    Good value: <=130

    184.5 mm
    Onyx Boox Tab Ultra C is 184.5 mm wide which is wider than 84.4% of eReaders on this spec and equal to 0.8% of eReaders.
    Water resistance (splashproof)
    What it is: Can tolerate light splashes, damp hands, or brief accidental contact with water.
    When it matters: When you read by the bath, at the pool, or outdoors where light moisture is realistic.

    Importance: MEDIUM

    no
    Onyx Boox Tab Ultra C does not have water resistance against splashes. 25% of eReaders have water resistance against splashes.
    Show more

    Onyx Boox Tab Ultra C vs the average eReader

    • 4.12x larger battery capacity
      Onyx Boox Tab Ultra C has a larger battery than the average eReader (6,300 mAh vs 1,530 mAh). The average eReader battery has a capacity of 1,530 mAh.
      What it is: The amount of energy the battery can store, commonly expressed in mAh.
      When it matters: When you want a rough hardware indicator of how much power reserve the device has.

      Importance: MEDIUM

      Good value: >=2000

      Onyx Boox Tab Ultra C has a larger battery than the average eReader (6,300 mAh vs 1,530 mAh). The average eReader battery has a capacity of 1,530 mAh.6,300 mAh vs 1,530 mAh
    • 3.3 inches larger screen size
      Onyx Boox Tab Ultra C has a larger screen than the average eReader (10.3 inches vs 7 inches). The average eReader screen size is 7 inches.
      What it is: The diagonal measurement of the reading panel, usually given in inches.
      When it matters: When you are deciding between a small travel reader and a larger page that works better for PDFs, comics, or textbooks.

      Importance: HIGH

      Good value: >=7.8

      Onyx Boox Tab Ultra C has a larger screen than the average eReader (10.3 inches vs 7 inches). The average eReader screen size is 7 inches.10.3 inches vs 7 inches
    • 8x more storage
      Onyx Boox Tab Ultra C offers more internal storage than the average eReader (128 GB vs 16 GB). The average eReader provides 16 GB of internal storage.
      What it is: The built-in space available for books, notes, audiobooks, apps, and downloaded documents.
      When it matters: When you keep large libraries offline or store a lot of PDFs and audio locally.

      Importance: HIGH

      Good value: >=32

      Onyx Boox Tab Ultra C offers more internal storage than the average eReader (128 GB vs 16 GB). The average eReader provides 16 GB of internal storage.128 GB vs 16 GB
    • Higher screen resolution
      Onyx Boox Tab Ultra C supports higher screen resolution than the average eReader (1860x2480 px vs 1072x1448 px). The average eReader supports 1072x1448 px screen resolution.
      What it is: The total pixel grid shown on the panel, normally written as width by height.
      When it matters: When small fonts, diagrams, or dense page layouts need to stay readable without constant zooming.

      Importance: HIGH

      Onyx Boox Tab Ultra C supports higher screen resolution than the average eReader (1860x2480 px vs 1072x1448 px). The average eReader supports 1072x1448 px screen resolution.1860x2480 px vs 1072x1448 px
    • 9 broader file support
      Onyx Boox Tab Ultra C supports a broader range of file types than the average eReader (24 vs 15).
      What it is: Lists which ebook, document, image, or audio formats the reader can open without conversion.
      When it matters: When your library comes from mixed sources instead of one locked bookstore.

      Importance: HIGH

      Onyx Boox Tab Ultra C supports a broader range of file types than the average eReader (24 vs 15).24 vs 15
    • Has color display
      Onyx Boox Tab Ultra C has a color display, while the average eReader does not.
      What it is: Shows color instead of grayscale only, usually through a color E Ink panel with more muted tones than LCD or OLED screens.
      When it matters: When you read comics, illustrated books, magazines, or documents that rely on color-coded charts and highlights.

      Importance: MEDIUM

      Onyx Boox Tab Ultra C has a color display, while the average eReader does not.
    • Supports handwriting recognition
      Onyx Boox Tab Ultra C supports handwriting recognition, while the average eReader does not.
      Built-in handwriting-to-text support.
      What it is: Can convert handwritten pen input into editable digital text.
      When it matters: When you write notes by hand and want them searchable, cleaner, or easier to export later.

      Importance: MEDIUM

      Onyx Boox Tab Ultra C supports handwriting recognition, while the average eReader does not.
    • 3.49 GB more RAM
      Onyx Boox Tab Ultra C has more RAM than the average eReader (4 GB vs 0.512 GB). The average eReader has 0.512 GB of RAM.
      What it is: The amount of working memory used for page rendering, multitasking, and keeping content active in the background.
      When it matters: When you open heavy files, switch between books, or expect the interface to stay snappy.

      Importance: MEDIUM

      Good value: >=2

      Onyx Boox Tab Ultra C has more RAM than the average eReader (4 GB vs 0.512 GB). The average eReader has 0.512 GB of RAM.4 GB vs 0.512 GB
    • 3.3 inches larger screen size
      Onyx Boox Tab Ultra C has a larger screen than the average eReader (10.3 inches vs 7 inches). The average eReader screen size is 7 inches.
    • Higher screen resolution
      Onyx Boox Tab Ultra C supports higher screen resolution than the average eReader (1860x2480 px vs 1072x1448 px). The average eReader supports 1072x1448 px screen resolution.
    • Has color display
      Onyx Boox Tab Ultra C has a color display, while the average eReader does not.
    • More advanced E-Ink technology
      Onyx Boox Tab Ultra C uses Kaleido 3 E-Ink technology, while the average eReader uses Carta Plus.
    • 13.2% higher pixel density
      Onyx Boox Tab Ultra C has a higher pixel density than the average eReader (300 ppi vs 265 ppi). The average eReader has a pixel density of 265 ppi.
    • Supports auto-rotate
      Onyx Boox Tab Ultra C supports auto-rotate, while the average eReader does not.
    • 9 broader file support
      Onyx Boox Tab Ultra C supports a broader range of file types than the average eReader (24 vs 15).
    • Supports handwriting recognition
      Onyx Boox Tab Ultra C supports handwriting recognition, while the average eReader does not.
    • Supports stylus
      Onyx Boox Tab Ultra C supports a stylus, while the average eReader does not.
    • Broader library support
      Onyx Boox Tab Ultra C supports more library lending platforms than the average eReader (OverDrive, Libby, Hoopla, BorrowBox vs OverDrive, Libby).
    • Includes stylus
      Onyx Boox Tab Ultra C includes a stylus, while the average eReader does not.
    • 4.12x larger battery capacity
      Onyx Boox Tab Ultra C has a larger battery than the average eReader (6,300 mAh vs 1,530 mAh). The average eReader battery has a capacity of 1,530 mAh.
    • 8x more storage
      Onyx Boox Tab Ultra C offers more internal storage than the average eReader (128 GB vs 16 GB). The average eReader provides 16 GB of internal storage.
    • Includes memory card slot
      Onyx Boox Tab Ultra C includes a memory card slot, while the average eReader does not.
    • 3.49 GB more RAM
      Onyx Boox Tab Ultra C has more RAM than the average eReader (4 GB vs 0.512 GB). The average eReader has 0.512 GB of RAM.
    • Faster CPU base clock speed
      Onyx Boox Tab Ultra C has a faster CPU base clock speed than the average eReader (8x2 GHz vs 1x1 GHz). The average eReader has a CPU base clock speed of 1x1 GHz.
    • More advanced operating system
      Onyx Boox Tab Ultra C uses Android 11, a more advanced operating system than Kindle OS on the average eReader.
    • Has accelerometer
      Onyx Boox Tab Ultra C has an accelerometer, while the average eReader does not.
    • Has fingerprint scanner
      Onyx Boox Tab Ultra C has a fingerprint scanner, while the average eReader does not.
    • Has microphone
      Onyx Boox Tab Ultra C has a microphone, while the average eReader does not.
    • Supports USB OTG
      Onyx Boox Tab Ultra C supports USB OTG, while the average eReader does not.
    • 2 more speakers
      Onyx Boox Tab Ultra C has more speakers than the average eReader (2 vs 0). The average eReader has 0 speakers.
    • Better Wi-Fi bands
      Onyx Boox Tab Ultra C supports 2.4 GHz+5 GHz Wi-Fi bands, while the average eReader supports 2.4 GHz.
    • 1.4 mm thinner
      Onyx Boox Tab Ultra C is thinner than the average eReader (6.7 mm vs 8.1 mm). The average eReader thickness is 8.1 mm.
    • 2 year/s newer release date
      Onyx Boox Tab Ultra C is newer than the average eReader (2023 vs 2021). The average eReader was released in 2021.

    Total
    Display
    Reading
    Battery
    Hardware
    Connectivity
    Design
    • 1 hours shorter battery life
      Onyx Boox Tab Ultra C offers shorter battery life than the average eReader (20 hours vs 21 hours). The average eReader offers 21 hours of battery life.
      highly variable, around 14h with 100% frontlight, but can last multiple days with typical usage
    • Older Bluetooth version
      Onyx Boox Tab Ultra C supports an older Bluetooth version than the average eReader (5 vs 5.1).
    • 2.25x heavier
      Onyx Boox Tab Ultra C is heavier than the average eReader (480 g vs 213 g). The average eReader weighs 213 g.
    • 56.9 mm wider
      Onyx Boox Tab Ultra C is wider than the average eReader (184.5 mm vs 127.6 mm). The average eReader width is 127.6 mm.
    • 52 mm taller
      Onyx Boox Tab Ultra C is taller than the average eReader (225 mm vs 173 mm). The average eReader height is 173 mm.
    • 2.25x heavier
      Onyx Boox Tab Ultra C is heavier than the average eReader (480 g vs 213 g). The average eReader weighs 213 g.
      What it is: The mass of the device, usually measured in grams.
      When it matters: When one-handed comfort matters and you do not want the reader to feel tiring during long sessions.

      Importance: HIGH

      Good value: <=200

      Onyx Boox Tab Ultra C is heavier than the average eReader (480 g vs 213 g). The average eReader weighs 213 g.480 g vs 213 g
    • 56.9 mm wider
      Onyx Boox Tab Ultra C is wider than the average eReader (184.5 mm vs 127.6 mm). The average eReader width is 127.6 mm.
      What it is: The side-to-side body measurement, usually given in millimetres.
      When it matters: When one-handed reach and how much space the reader takes in a bag or bedside setup matter.

      Importance: LOW

      Good value: <=130

      Onyx Boox Tab Ultra C is wider than the average eReader (184.5 mm vs 127.6 mm). The average eReader width is 127.6 mm.184.5 mm vs 127.6 mm
    • 1 hours shorter battery life
      Onyx Boox Tab Ultra C offers shorter battery life than the average eReader (20 hours vs 21 hours). The average eReader offers 21 hours of battery life.
      highly variable, around 14h with 100% frontlight, but can last multiple days with typical usage
      What it is: Estimates how long the device can keep running between charges under normal reading conditions.
      When it matters: When you travel, commute, or want to finish books for days without thinking about charging.

      Importance: HIGH

      Good value: >=30

      Onyx Boox Tab Ultra C offers shorter battery life than the average eReader (20 hours vs 21 hours). The average eReader offers 21 hours of battery life.20 hours vs 21 hours
    • 3.35x more expensive
      Onyx Boox Tab Ultra C is more expensive than the average eReader (£570 vs £170).
      Onyx Boox Tab Ultra C is more expensive than the average eReader (£570 vs £170).£570 vs £170
    • 52 mm taller
      Onyx Boox Tab Ultra C is taller than the average eReader (225 mm vs 173 mm). The average eReader height is 173 mm.
      What it is: The vertical size of the body, usually measured from top to bottom in millimetres.
      When it matters: When you are checking whether the reader will fit a bag, jacket pocket, or small stand.

      Importance: LOW

      Good value: <=160

      Onyx Boox Tab Ultra C is taller than the average eReader (225 mm vs 173 mm). The average eReader height is 173 mm.225 mm vs 173 mm
    • Older Bluetooth version
      Onyx Boox Tab Ultra C supports an older Bluetooth version than the average eReader (5 vs 5.1).
      What it is: Identifies the supported Bluetooth generation, which affects efficiency, codec support, and compatibility.
      When it matters: When you pair newer headphones and want a more stable, lower-power wireless connection.

      Importance: LOW

      Good value: >=5.0

      Onyx Boox Tab Ultra C supports an older Bluetooth version than the average eReader (5 vs 5.1).5.0 vs 5.1
    • 7.7% lower user score
      Onyx Boox Tab Ultra C has a lower user score than the average eReader (7.43 vs 8,000).
      What it is: A rating that combines user reviews and the total number of reviews received by the eReader.
      When it matters: When you want to know how an eReader feels in daily reading and how reliable it is for screen comfort, battery life, and library management according to user feedback.
      Onyx Boox Tab Ultra C has a lower user score than the average eReader (7.43 vs 8,000).7.43 vs 8
    Total
    Overall
    Battery
    Connectivity
    Design

    Graphic comparison of Onyx Boox Tab Ultra C and other eReaders

    Attribute category
    Attribute
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    Third-party reviews

    United States
    Amazon_logo.png
    3.7
    144 Reviews
    United Kingdom
    amazon
    3.7
    133 Reviews
    amazon
    3.9
    132 Reviews
    amazon
    3.7
    21 Reviews

    (Reviews last updated: Apr 2026)

    What customers like about Onyx Boox Tab Ultra C?

    • Versatile Kaleido 3 color E-Ink display that significantly enhances comics, magazines, and technical documents compared to grayscale models.
    • Full Android OS with Google Play Store support, allowing for a wide range of third-party apps like Kindle, Libby, and productivity tools.
    • Powerful hardware for an e-reader, including an octa-core processor and dedicated GPU (BSR technology) for smoother refreshing and less ghosting.
    • Excellent for note-taking and PDF annotation with the included low-latency Wacom stylus and robust first-party software.
    • Premium build quality with a sleek metal chassis and integrated fingerprint sensor for security.
    • Large 10.3-inch screen provides ample space for A5-sized documents and split-screen multitasking.

    What customers dislike about Onyx Boox Tab Ultra C?

    • High price point compared to monochrome competitors like the Kindle Scribe or ReMarkable 2.
    • Color saturation and vibrancy are muted and 'pastel-like' compared to traditional LCD or OLED tablets.
    • Noticeably darker screen than monochrome E-Ink devices, often requiring the front light even in well-lit rooms.
    • Battery life is shorter than typical e-readers (lasting days rather than weeks) due to the higher power demands of the Android system and BSR tech.
    • The 16MP rear camera is often described as mediocre or 'superfluous' for anything other than basic document scanning.
    • Relatively heavy and dense at 480g-490g, making it less comfortable for extended one-handed reading.

    Expert reviews

    T
    theverge.com
    26/04/2023
    The new Onyx Boox Tab Ultra C is a color E Ink tablet with a 16-megapixel camera Would you like to see a comparison of how this model's 150ppi color r...

    The Onyx Boox Tab Ultra C is a 10.3-inch E Ink tablet featuring a Kaleido 3 color screen that serves as a versatile hybrid for reading and productivity. A major advantage is the 300ppi monochrome resolution alongside a 150ppi color mode for comics, powered by an open Android 11 system that supports Google Play apps. Key cons include washed-out, pastel-like colors compared to LCD...Read more

    A
    androidcentral.com
    10/05/2023
    Onyx Boox Tab Ultra C review: The best E Ink tablet, now in color

    The Onyx Boox Tab Ultra C is a 10.3-inch E Ink tablet featuring a 300 ppi Kaleido 3 color screen, making it ideal for color-coded note-taking, reading, and digital planning. Powered by Android 11 with an octa-core processor and dedicated GPU, it offers a fast, versatile experience supporting third-party apps like Kindle and Slack. Key advantages include its crisp color display,...Read more

    E
    expertreviews.co.uk
    23/06/2023
    Onyx Boox Tab Ultra C review: The most flexible e-ink tablet

    The Onyx Boox Tab Ultra C is a versatile 10.3-inch E Ink tablet featuring a Kaleido 3 color display and Android 11, allowing for diverse app usage via the Google Play Store. Key advantages include an excellent note-taking experience, a responsive stylus, and long-lasting battery life. However, the device is heavy (480g) and expensive at approximately £558, making it a premium...Read more

    T
    trustedreviews.com
    06/10/2023
    Onyx Boox Tab Ultra C Review

    The Onyx Boox Tab Ultra C is described as a well-constructed, 10.3-inch Kaleido 3 colour E Ink device that bridges the gap between an e-reader and a tablet. It features a premium design and a responsive stylus for note-taking, but its performance struggles with demanding tablet tasks like media playback. While boasting exceptional, long-lasting battery life and useful, productive...Read more

    T
    t3.com
    21/08/2023
    Onyx Boox Tab Ultra C review: colour me E Ink - T3

    The T3 review highlights the Onyx Boox Tab Ultra C's unique Kaleido 3 color E Ink screen as a versatile, eye-friendly option for reading, boasting excellent app support via the Google Play Store and a natural-feeling stylus. While praised for its solid build, long battery life, and superior, low-brightness night reading, the device is positioned as a niche productivity tool rather...Read more

    T
    techradar.com
    14/06/2023
    Onyx Boox Tab Ultra C review - eReaders - TechRadar

    The TechRadar review describes the 10.3-inch Onyx Boox Tab Ultra C as a versatile E Ink tablet featuring a Kaleido 3 display (300 PPI black-and-white, 150 PPI color) that is excellent for reading and annotating, though colors are muted. A major pro is access to the Google Play Store on Android 11, while the responsive Wacom-powered stylus offers an exceptional note-taking...Read more

    P
    pcmag.com
    13/07/2023
    Onyx Boox Tab Ultra C Review

    The Onyx Boox Tab Ultra C is a 10.3-inch E Ink Kaleido 3 hybrid, bridging the gap between an e-reader and an Android tablet with features like a 300ppi monochrome display, a 6,300mAh battery, and Google Play Store access. Key advantages include its versatile functionality, premium build, and color e-paper capabilities for note-taking and reading, according to PCMag. However, the...Read more

    C
    catominor3.medium.com
    29/05/2023
    My first impressions of the Onyx Boox Tab Ultra C - Cato Minor Would you like a similar list for the Tab Ultra C Pro or a comparison between the two m...

    Cato Minor’s review highlights the Onyx Boox Tab Ultra C as a versatile hybrid device, combining E Ink technology with Android tablet functionality. Key pros include the 300 PPI Kaleido 3 color screen, which enhances reading, and a highly responsive stylus for note-taking. The device's performance is further supported by a capable processor and optional keyboard, though it is...Read more

    Y
    yankodesign.com
    26/05/2023
    Onyx Boox Tab Ultra C Review: Delightful Heavyweight

    The Onyx Boox Tab Ultra C is a 10.3-inch color E-Ink tablet featuring Kaleido 3 technology and a dedicated GPU, offering a responsive, high-contrast experience for note-taking and app usage. Its primary pros include Android 11 flexibility, a capable 16MP camera, and a superior writing experience, though it remains a heavy, thick device that compromises on portability. While the...Read more

    U
    uk.pcmag.com
    13/07/2023
    Onyx Boox Tab Ultra C - Review 2023 - PCMag UK

    The Onyx Boox Tab Ultra C is a high-performance 10.3-inch E Ink hybrid running Android 11, featuring a Kaleido 3 color screen, a 16MP camera for document scanning, and a premium, sturdy design. While praised for its exceptional battery life and note-taking capabilities, the device suffers from poor color saturation, a slow refresh rate, and mediocre, thin-sounding audio. With a high...Read more

    Z
    zdnet.fr
    15/05/2023
    Onyx Boox Tab Ultra C Review: The Best E Ink Tablet Goes Color

    The Onyx Boox Tab Ultra is a 10.3-inch, Android-based e-ink tablet featuring Boox Super Refresh (BSR) technology for fast, fluid navigation suitable for productivity. It boasts a premium aluminum design, a responsive Wacom stylus for paper-like note-taking, and Google Play Store access, enabling the use of apps like Obsidian. Key advantages include its versatility as a document...Read more

    (Translated)Show original
    T
    techprincess.it
    26/04/2023
    Onyx BOOX Tab Ultra C: E-Ink Tablet with Pastel Colors

    The Onyx Boox Tab Ultra C is a 10.3-inch E Ink tablet featuring a Kaleido 3 color screen with 300 ppi for black-and-white and 150 ppi for color, powered by Android 11 for app accessibility. Key advantages include the Boox Super Refresh (BSR) technology for faster screen responsiveness, a precise stylus, and expandable storage, though the device is heavy and features muted,...Read more

    (Translated)Show original
    T
    today.it
    22/08/2023
    Onyx Boox Tab Ultra C: E-reader, tablet, and digital notebook

    The Onyx Boox Tab Ultra C is a 10.3-inch E Ink tablet featuring a Kaleido 3 color display, designed for reading and document management with a 4,096-color palette and a 16-megapixel camera for OCR. It functions as a productivity tool, running Android 11 with a Qualcomm processor and Wacom stylus support for taking notes on documents. Key advantages include smooth performance via...Read more

    (Translated)Show original
    S
    smartworld.it
    05/08/2023
    Onyx BOOX Tab Ultra C Review: Finally in Color!

    The Onyx Boox Tab Ultra C is a 10.3-inch E Ink tablet featuring a Kaleido 3 color display and Android 11 with Google Play Store access, bridging the gap between productivity and e-reading. Powered by a Snapdragon processor and "Super Refresh" technology, it offers smooth scrolling and a 6,300mAh battery, though the screen is noticeably darker, requiring front light usage. Pros...Read more

    (Translated)Show original
    T
    tuttotech.net
    09/09/2023
    Onyx BOOX Tab Ultra C Review: Tablet, Computer, E-reader

    The Onyx Boox Tab Ultra C is a 10.3-inch hybrid E-Ink tablet featuring a Kaleido 3 color display with 300 PPI for monochrome and 150 PPI for color, offering a superior, albeit muted, color experience for reading and note-taking. Driven by a Snapdragon 665 processor, 4GB of RAM, and Android 11, it functions as a highly productive, versatile device with full Google Play Store access....Read more

    (Translated)Show original

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