Contrast Checker WCAG AA AAA

Color Accessibility Ratio Test

Only for iPhone

Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.

iPhone

Pick two colors, get the exact WCAG 2.1 verdict - AA and AAA, normal and large text - plus the closest passing shade when a pair fails. All on-device. Check the contrast ratio between any text and background color against WCAG 2.1 - the same AA and AAA thresholds you verify on the web, now in your pocket. Pick two colors and Contrast Checker shows the exact ratio and a pass/fail verdict for every level before your UI ships. The math is implemented verbatim from the W3C specification: 8-bit sRGB relative luminance, the exact 4.5:1 / 3:1 / 7:1 thresholds, no rounding tricks. The hex code on screen is precisely the color the ratio was computed from - even when the system picker hands back a Display P3 color. And when a pair fails, Contrast Checker does not just say no: it finds the closest passing shade for you. WHAT YOU GET • The exact ratio - 4.61:1, not "looks fine" - recalculated live as you drag the color picker or paste a hex code • Four verdicts at a glance: AA and AAA, for both normal and large text, so you know exactly which compliance claim you can make • A one-tap fix when a pair fails: the nearest darker and the nearest lighter foreground shade that reach your target, background untouched • A live mock UI - headline, body copy, buttons - rendered in your exact colors, so you see the pair working before you commit it • A palette audit that checks a whole theme on one screen: "5 of 6 pass AA" instead of six separate lookups • A compliance report of your saved pairs - hex codes, ratios, pass/fail per level - ready to paste into a ticket, PR, or client handoff PERFECT FOR • Designers proving a design-system palette passes before handoff • iOS and web developers closing accessibility tickets with evidence instead of opinion • Agencies and freelancers who must document ADA / WCAG compliance for clients • Anyone tired of retyping hex codes into a website on a laptop to settle a color argument WHY NOT JUST USE A WEB CHECKER? Because the web checker is on your other machine, needs a connection, makes you type hex codes by hand, forgets every pair you ever tested - and when a color fails, it shrugs. Contrast Checker runs offline, uses real color pickers, remembers your pairs by project, and answers a failing check with the exact shade that passes. PRIVATE BY DEFAULT Every calculation happens on your device. No account, no sign-in, no uploads - your colors, palettes, and reports never leave your phone. FULL ACCESS Full Access unlocks unlimited saved pairs, unlimited rows in the palette audit, and export of the shareable compliance report. Choose a Weekly or Yearly auto-renewing subscription, or a one-time Lifetime purchase. Download Contrast Checker, drop in the two hex codes you are unsure about, and have your AA verdict before your coffee cools. Terms of Use: https://leanstudio.asia/terms-of-use Privacy Policy: https://leanstudio.asia/privacy-policy Support: support@leanstudio.asia

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First release. Check any color pair against WCAG 2.1 — AA and AAA, for normal and large text.

Version 1.1

Subscriptions

In-App Purchases

The developer, LEAN ASIA CO., LTD, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    LEAN ASIA CO., LTD
    Size
    2.8 MB
    Category
    Developer Tools
    Compatibility
    Requires iOS 17.0 or later.
    • iPhone
      Requires iOS 17.0 or later.
    • Mac
      Requires macOS 14.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Languages
    English
    Age Rating
    4+
    In-App Purchases
    Yes
    • UI Design Lifetime $19.99
    • Palette Audit Yearly $9.99
    • Readability Weekly $1.99
    • Learn More
    Copyright
    © 2026 LEAN ASIA CO., LTD
  • Developer Website
  • Privacy Policy

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