Color contrast checker
Acrobat's checker won't test contrast — it just says “needs manual check.” This does the test. Click an example, or type any two colors.
Contrast result and controls
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Large heading sample (26px bold)
Normal body text at 16px — the size most content uses. Can you read this comfortably?
Try an example:
About “Swap”: the ratio is the same both ways — contrast doesn't care which color is text and which is background. Swapping just flips the preview so you can see readability each way. AA needs 4.5:1 for normal text and 3:1 for large text (≥18pt, or ≥14pt bold) and UI/icons.