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Color & Design tool

Contrast Checker

Check WCAG contrast ratios for text and backgrounds.

Runs on-deviceNo sign-upFree
All color & design tools

Contrast Checker workspace

Workspace

Contrast Checker

Runs locally

Screen-accurate enough

Values are calculated on the fly. CMYK is an approximation for screen preview; use a colour-managed proof for print.

Foreground #12130fBackground #c6f24e

Readable by design.

14.40:1WCAG AA pass
Values & CSS0 chars

The guide

By the utils.sbs team · Reviewed November 2026 · How we build and review tools

Quick answer

Contrast Checker is a free browser-based color & design tool. Check WCAG contrast ratios for text and backgrounds. It runs with JavaScript and Canvas colour conversions locally, requires no account and does not upload your files. Open the page, add your input, adjust any options and download the result.

What is Contrast Checker?

Contrast Checker is a free browser-based color & design tool from utils.sbs. Check WCAG contrast ratios for text and backgrounds. It is built for quick, focused jobs: open the page, add your input, adjust the options and take the result with you. No account, install or server upload is required.

At a glance

CategoryColor & Design
InputHEX, RGB or HSL values, or an image for colour sampling
OutputCSS, JSON or a generated colour palette
EngineJavaScript and Canvas colour conversions
ProcessingIn your browser
PriceFree
AccountNot required

How Contrast Checker works

Colour values are converted with standard colour-space formulas and generated as CSS, design tokens or image palettes.

How to use Contrast Checker

  1. 1Open Contrast Checker and add your input.
  2. 2Adjust the options: foreground, background.
  3. 3Run the tool, check the preview or result, and download the output.

When to use Contrast Checker

  • Build a palette for a website or design system.
  • Convert colour values between HEX, RGB and HSL.
  • Check contrast or sample colours from an image.

Inputs and options

Foreground
Set this value before running the tool.
Background
Set this value before running the tool.

Limitations

Screen colour and colour-space differences can change how values appear on other devices.

Privacy and accuracy

Contrast Checker processes its input in the browser whenever the platform API allows it. Files and values are not uploaded to a server for processing, and the tool does not require an account. For calculations, use the result as a reference and verify important decisions against the source formula or a qualified professional. Read our methodology.

FAQ

Contrast Checker questions

  • What can I do with Contrast Checker?

    Check WCAG contrast ratios for text and backgrounds. Contrast Checker is part of the Color & Design shelf on utils.sbs and is designed for quick, one-off tasks.

  • Is Contrast Checker free to use?

    Yes. Contrast Checker is free, requires no account, and has no per-file or per-use charge.

  • Are my files uploaded when I use Contrast Checker?

    No. Contrast Checker is designed to process your input locally in the browser. Files are not uploaded to a server for processing.

  • What formats does Contrast Checker support?

    It accepts colour values and returns CSS, JSON or a generated palette that you can copy or download.

  • Can I use Contrast Checker on my phone?

    Yes. Contrast Checker is responsive and works in modern mobile browsers. Very large files may be limited by the device's available memory.

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