Colour, worked out instead of guessed at
Three things a swatch picker cannot do: tell you whether a pair is readable, tell you what your colour has to become to be readable without changing its hue, and tell you how far apart two colours actually are to a human eye.
Check a pair, and fix it
Text colour
Background
Body text at this size
And the smaller size most interfaces actually use for paragraphs.
WCAG 2.1 contrast ratio
5.47:1
Passes AA for body text
The normative measure. It does not know which of the two is the text.
- ✓AA · body text 4.5:1
- ✓AA · large text 3:1
- ✕AAA · body text 7:1
- ✓Icons and borders 3:1
APCA lightness contrast
Lc 77.3
Clears Lc 75 — body text at a normal size and weight.
Positive: dark text on a lighter background.
And to someone who does not see all three cones
Contrast is a brightness question, so it survives colour vision deficiency — but two colours that differ only in hue do not. All three simulations.
Six tools, one rule
Everything runs in your browser on the same code that built the pages. Nothing you type, pick or drop is sent anywhere, because there is nowhere to send it: this site's whole API is a visit counter.
Tool
Contrast, and the fix
WCAG 2.1 and APCA together, plus the nearest colour of the same hue that passes.
Tool
How different two colours are
CIEDE2000, checked against the 34 pairs its authors published for exactly this purpose.
Tool
Colour vision deficiency
Which pairs in your palette stop being two colours for someone missing a cone.
Tool
A palette from a picture
Clustered in OKLab, in this browser. There is nowhere on this site to send a file.
Tool
Scales and harmonies
Eleven steps in OKLCh, with a count of how many of them a reader can actually tell apart.
Tool
4,692 pairs, already measured
Text on background, both verdicts, the fix, and what each dichromacy does to it.
Why the second answer matters
Every checker tells you
that you failed, and leaves you nudging the hex by hand until the number goes green.
This one tells you
the nearest colour that passes with the same hue — your brand colour, still recognisable.
And when nothing passes
it says so. On a mid-tone background no colour reaches 4.5:1, and pretending otherwise would waste your afternoon.
The search runs in OKLCh, where lightness moves without dragging hue with it. In the older CIELCh space the same search turns a saturated blue towards purple on the way.
Browse 31,916 named colours
By hue family, with the twelve perceptually nearest colours on every page — computed with CIEDE2000, not by sorting hex codes.
Nothing here is an opinion
The colour-difference formula is checked against the 34 reference pairs its authors published; APCA against 900 pairs generated by its own reference implementation; the conversions against the sRGB primaries as CSS Color 4 defines them, and by round trip; the contrast ratio against the one value anyone can verify by hand — black on white is exactly 21:1. How each number is checked.
No account. No proprietary colour system, because those belong to their owners and republishing them is not ours to do.