Complementary Color Generator
A complementary color is the color directly opposite on the color wheel, 180° away in hue. To find it, keep the same saturation and lightness and rotate the hue by 180°. For example, the complement of blue #0000FF is yellow #FFFF00. Enter any HEX code to see its complement and other harmonies.
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What complementary colors are
Complementary colors sit opposite each other on the color wheel. On screens the wheel is built from red, green and blue light, so the pairs are red–cyan, green–magenta and blue–yellow. This tool keeps the saturation and lightness of your color and rotates only the hue, so the complement has the same strength as the original.
Painters use the traditional red-yellow-blue (RYB) wheel, where red pairs with green and blue with orange. This generator does not use RYB, because HEX codes describe screen colors.
How to use complementary colors
- Use the complement as an accent (about 10%, as in the 60-30-10 rule), not as an equal partner.
- Soften one side: a darker or lighter version of the complement is easier on the eye than two full-strength hues.
- Never put full-strength complements as text on each other; check the pair with the contrast checker.
Frequently asked questions
What is the complementary color of red?
On the RGB color wheel used for screens (and by this tool), the complement of red #FF0000 is cyan #00FFFF. On the traditional painter's RYB wheel, red's complement is green. This generator uses the RGB/HSL wheel because it works with HEX codes.
Are complementary colors good together?
Yes, as contrast. Opposite hues make each other look more intense, which is great for a call-to-action button or highlight. Used 50/50 at full saturation they can clash, so let one color dominate and use the complement as an accent.
What is split-complementary?
Split-complementary uses the base color plus the two colors on either side of its complement, 150° and 210° from the base. It keeps strong contrast but is easier to balance than a straight complementary pair.