Contrast Checker
Ensure your text is readable and accessible with WCAG color contrast validation.
Design tool guide · Color selection and accessibility
About Color Contrast Checker
The Contrast Checker compares foreground and background colors and reports a contrast ratio. The result can help evaluate text readability against WCAG contrast thresholds, but it does not review an entire page or replace testing with users and assistive technology.
Color tools help inspect, compare, and create colors for an interface or graphic. A displayed HEX, RGB, HSL, palette, harmony, or contrast result describes specific color values; it does not automatically account for every font size, display, state, or accessibility need in a finished design.
How to Use This Tool
- 1.Enter or select the foreground text color and the background color.
- 2.Read the calculated ratio and the pass/fail indicators for the relevant text size category.
- 3.Adjust one or both colors and retest. Check every state, including links, focus, hover, disabled, and error text.
Key Details About Color Contrast Checker
1.Color formats describe the same color differently
HEX and RGB express channel values, while HSL describes hue, saturation, and lightness. Conversions can be rounded for display, so small differences in the final digits may occur without a meaningful visible change.
2.Palettes are design suggestions
Generated palettes and harmonies offer combinations based on color relationships. Use them as options, then decide which colors fit the brand, content hierarchy, and interaction states.
3.Contrast depends on the pair
A contrast ratio compares foreground and background colors. Check the actual text or control color against its surface; nearby colors in a palette do not tell you whether a particular pair is readable.
4.Simulation is an approximation
Color blindness simulations can help reveal possible perception differences, but they do not reproduce every person's vision or every display. Do not use color alone to convey important information.
How the Tool Works
The checker converts sRGB channel values to relative luminance, then computes (lighter luminance + 0.05) ÷ (darker luminance + 0.05). WCAG 2.x AA generally requires 4.5:1 for normal text and 3:1 for large text; other criteria apply to non-text UI components.
Example
Black on white has a contrast ratio of 21:1, the maximum in the standard calculation. A lighter gray on white has a lower ratio and may fail normal-text guidance.
Where You Can Use Color Contrast Checker
Check text color pairs, tune buttons, and verify common UI combinations before design review.
Choosing interface colors
Explore a palette or harmony, then assign colors to clear roles such as background, text, border, and action.
Checking a text treatment
Enter the foreground and background values used by the design and review the ratio alongside the size and weight of the real text.
Matching an existing color
Use the picker or extracted palette to inspect a source color, then copy the format expected by your CSS, graphics, or design software.
Reviewing non-color cues
Use a simulation as one check, and make sure status, selection, errors, and charts also use labels, shapes, icons, or patterns.
Tips for Better Results
- Copy the exact color format your project expects and verify the value after pasting it.
- Check every important foreground and background pairing, including hover, disabled, and focus states.
- Review contrast with the actual font size and weight rather than judging by appearance alone.
- Do not communicate errors or status using color only; add text or another clear visual cue.
- Compare colors on more than one display when accurate brand matching matters.
Technical Limits and Review
The tool checks only the colors entered and does not inspect font weight, image text, transparency layers, gradients, or the whole page. WCAG conformance needs broader review and the applicable criterion for each element.
Color results are based on the values or pixels supplied and the calculation shown by the tool. Display calibration, transparency, surrounding colors, font rendering, and individual perception can affect the final experience. Treat contrast and simulation results as useful checks within a broader design review.
Frequently Asked Questions
What ratio should normal text meet for WCAG AA?
The usual threshold is at least 4.5:1 for normal text.
Does passing this tool make a website accessible?
No. It checks one color pair; accessibility includes many other requirements.
Does a larger heading have a different threshold?
Large text generally has a 3:1 minimum under WCAG AA contrast guidance.
Which color format should I copy?
Use the format required by the destination. CSS supports common HEX, RGB, and HSL forms, while other software may prefer a specific format.
Does a passing contrast result mean the whole page is accessible?
No. It applies to the tested pair and does not check labels, focus, states, layout, or all accessibility needs.
Why does an extracted color differ from the image?
Image compression, transparency, scaling, and nearby pixels can affect sampled values.
Are generated color harmonies guaranteed to look good?
They provide a mathematical relationship, but visual fit depends on context, content, and the design's purpose.