🎨 Paint Color Mixing Calculator

This calculator uses the standard RGB-to-CMYK conversion formula used in printing and color-theory to approximate subtractive mixing proportions. First, divide R, G, and B each by 255 to get values from 0 to 1. K = 1 − max(R,G,B). If K is less than 1: C = (1−R−K) ÷ (1−K), M = (1−G−K) ÷ (1−K), Y = (1−B−K) ÷ (1−K); if K equals 1 (pure black), C=M=Y=0. Multiply each by 100 to get a percentage. For example, with R=200, G=100, B=50: r=0.784, g=0.392, b=0.196, so K = 1 − 0.784 = 0.216, C = (1−0.784−0.216)/(1−0.216) = 0, M = (1−0.392−0.216)/0.784 = 0.5 → 50.0%, Y = (1−0.196−0.216)/0.784 = 0.75 → 75.0%.


This is an idealized subtractive-color-model approximation (the same math used for CMYK printing conversion) — real paint pigments are not perfectly subtractive. Results vary significantly by paint brand, pigment opacity/tinting strength, and finish, so always test-mix a small swatch before committing to a full batch.

The CMYK conversion formula assumes an idealized subtractive color space — that each ink/pigment absorbs a specific wavelength of light exactly, and darkens linearly as layers are combined. Real paint deviates from this in several ways: (1) pigments differ in opacity and tinting strength, so even a small amount can shift the color dramatically; (2) different brands and manufacturers use different pigment blends and purity, so the same ratio can look different across products; (3) a glossy vs. matte finish changes the perceived saturation and value; (4) black pigment (K) often mutes other colors more strongly than the calculated percentage suggests, so painters commonly use less black than the formula implies. Treat this calculator's output as a starting point, and always test-mix a small swatch to confirm visually before committing to a full batch.