ArtCalcs.uk
Complementary Colour Calculator
Find the complementary, split-complementary and triadic colours for any hue on the colour wheel.
How We Calculate This
This calculator finds colour relationships from a base hue on the artist’s 360° RYB (red-yellow-blue) colour wheel — the pigment-mixing wheel, not the digital RGB screen wheel. The three primaries sit 120° apart (Red 0°, Yellow 120°, Blue 240°), the secondaries between them (Orange 60°, Green 180°, Violet 300°), so the complement of red is green and the red triad is the primary trio red, yellow and blue.
Formulas
- Complementary: Base hue + 180°
- Split-complementary 1: Base hue + 150°
- Split-complementary 2: Base hue + 210°
- Triadic 1: Base hue + 120°
- Triadic 2: Base hue + 240°
The optional hue offset nudges the base hue a few degrees before the harmonies are found, so you can centre the scheme on the exact paint you mix rather than a textbook primary. Results wrap around the wheel (values stay between 0° and 359°).
Frequently Asked Questions
Complementary colours create visual excitement when placed side by side and muted tones when mixed together. Use them for shadows (add a touch of the complement to darken), focal points (small areas of complement draw the eye), and colour vibration (Impressionists used complementary strokes side by side).
Instead of using the direct complement, a split-complementary scheme uses the two colours on either side of the complement (150 and 210 degrees from the base). This gives similar contrast to a complementary scheme but with more nuance and is easier to work with.
When you mix two complementary colours, you are effectively combining all three primaries (the base colour plus the two primaries that make up its complement). Three primaries in roughly equal amounts produce a neutral grey or brown, depending on the specific pigments used.
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Last updated: February 2026
All calculations are estimates. Always verify quantities before purchasing materials.