Color Contrast Checker
WCAG contrast ratio between two colors
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Need a fast answer on WCAG contrast ratio between two colors? Color Contrast Checker answers with the steps beside it. Drop Foreground (hex) and Background (hex) into Color Contrast — the figure refreshes as you type. The answer from Color Contrast arrives with its working attached. That makes Color Contrast handy for quick estimates anywhere. Color Contrast runs in your browser. Tech & Digital data stays in the tab. Looking for color contrast checker wcag ratio accessibility or free online color contrast checker calculator? Color Contrast covers both. The labels in Color Contrast match the terms in its result. Start with Color Contrast; the first number takes seconds.
What does the Color Contrast Checker do?
Color Contrast Checker works out the wcag contrast ratio from the Foreground and Background, using Tech & Digital conventions. With the defaults, color contrast checker gives a wcag contrast ratio of 12.63:1.
- Inputs: Foreground and Background.
- Output: the wcag contrast ratio, plus the intermediate steps behind it.
- Method: the documented Tech & Digital method, with the wcag contrast ratio derived on your own machine.
Quick answer
color contrast checker returns a wcag contrast ratio of 12.63:1 with the default inputs (foreground of #333333, background of #ffffff).
How does the Color Contrast Checker work?
Color Contrast Checker computes the wcag contrast ratio directly from your inputs — the Foreground and Background feed the formula. Your figures are processed in place, which is why the wcag contrast ratio shows up instantly.
How it works
Every run of Color Contrast Checker evaluates the Foreground and Background you enter, applies the standard Tech & Digital formula, and reports the figure with each step listed for review.
Using the Color Contrast Checker
- Foreground — a core color contrast checker input applied directly — keep its units consistent with the label.
- Background — one of the values color contrast checker builds from; the result reflects exactly what you type.
- When the result on color contrast checker looks plausible but not quite right, check the units line first — a scale error shows up there before anywhere else.
- Nudge each Foreground and Background on the color contrast checker page in turn and note how far the wcag contrast ratio moves; the ranking rarely matches intuition.
The formula behind the result
The order of operations on the color contrast checker page is fixed by the Tech & Digital convention, which is why two runs with identical Foreground and Background cannot disagree.
Worked example: with foreground of #333333, background of #ffffff, this color contrast checker calculation returns 12.63:1. The same run reports AA ✓ (normal text).
The steps it follows:
- Compute relative luminance of each color
- Contrast = (L1+0.05) / (L2+0.05)
- WCAG: 4.5:1 for normal text, 3:1 for large text
Understanding the result
Work upward from the step list on the color contrast checker page and stop when the figures stop surprising you; that is the row your error is on.
Where it helps
Common ground for Color Contrast Checker: adjusting a plan mid-year, lining up two options, and checking a sum that someone else did, and any moment when a result needs to be explained rather than announced.
Common mistakes
Skipping the Foreground and Background because it looked optional is common, yet on Color Contrast Checker an empty-looking field still feeds the result.
Tip: Compare the color contrast checker answer with a hand calculation once; after that you will know which fields to watch in every later run.
Assumptions and limitations
Zero is treated as a real value throughout Color Contrast Checker, so a field left at zero changes the output rather than being skipped.
Why use this calculator
Because the color contrast checker page shows its assumptions rather than burying them, you can see which ones your own case breaks.
Frequently Asked Questions
What does color contrast checker compute?
At its core, Color Contrast Checker takes the Foreground and Background and evaluates the standard formula step by step, so the wcag contrast ratio can be checked rather than trusted on faith. Because the output is recalculated rather than remembered, Color Contrast Checker never hands you a stale figure left behind by someone else.
Where does the wcag contrast ratio come from?
The first steps are contrast = (l1+0.05) / (l2+0.05), then wcag: 4.5:1 for normal text, 3:1 for large text. No coefficient in Color Contrast Checker is tuned by guesswork: each term comes from the Tech & Digital definition, and the steps name the term that produced each figure in the figure.
Does Color Contrast Checker need anything besides its fields?
Only Foreground and Background — with the wcag contrast ratio following at once.
What does the result from the Color Contrast Checker mean?
The main number the color contrast checker returns is the wcag contrast ratio for your exact inputs. The color contrast checker calculation assumes the units printed on each label; a figure carried in from elsewhere keeps its digits and inherits the wrong scale.
What is the page best used for?
Reach for Color Contrast Checker when the task is adjusting a plan mid-year, lining up two options, and checking a sum that someone else did and an estimate from memory will not survive a second look. Run Color Contrast Checker twice with deliberately low and high inputs; the spread tells you how sensitive the output is, which a single run never shows.
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