Choose a color pair you can actually read
A color can look lovely as a large swatch and become difficult to read as small text. Judge a pair in the role it will actually play.
Name the role before choosing the shade
A background, paragraph text, border, and decorative accent do not have the same job. Start by naming what each color will do. If a pale green is intended as a calm background, pair it with a sufficiently dark text color rather than expecting another pale green to carry a paragraph. Keep a small set of roles so a page does not depend on a new color decision for every component.
Keep the numeric color consistent
HEX, RGB, and HSL can describe the same solid sRGB color. Use the converter when a design note and a style sheet use different formats. Check whether a source includes opacity: a six-digit HEX code does not preserve the alpha value of a transparent pixel. If you sampled a color from a photograph, remember that compression, lighting, and nearby pixels can all affect the value you chose.
Test the pair, not just each swatch
Put the proposed text color against the actual background in the contrast checker. The ratio belongs to that pair. A dark color that works against white can become weak against a dark panel. Passing the normal-text threshold is a practical starting point for paragraphs, but the checker’s result applies to opaque solid colors and selected text thresholds, not every possible component or state.
Do not rescue every weak pair by enlarging text
Some color pairs qualify only for large text at a given contrast level. That does not make them suitable for form hints, metadata, or body copy that will appear smaller. Choose a darker or lighter tone for the role instead of relying on all text being large or bold. Keep the threshold decision separate from the displayed ratio, which can be rounded near a boundary.
Inspect the real component
Look at the finished button, label, card, or paragraph at a normal viewing size. Check hover, focus, selected, disabled, and error states. A gradient or photograph needs more careful evaluation than a flat background because contrast can vary across the letter shapes. Do not rely on color alone to identify an error: add clear text, a label, or another visible indication of what changed.
Treat the checker as one step
A readable color pair is valuable, but keyboard navigation, focus visibility, label clarity, zoom behavior, and screen-reader access are separate concerns. Keep a short record of the chosen colors and where they are used. Test the final page on the devices you expect visitors to use, and consult the official W3C contrast guidance for the detailed requirements and exceptions.
References & further reading
Read the editorial & corrections policy for the scope of our checks and authorship.