Colour Blindness Simulator
Build a palette and see it the way viewers with colour vision deficiency do — then catch the colours that collapse into each other. Roughly 1 in 12 men and 1 in 200 women are affected. Everything runs in your browser.
How to read it. Each row shows your palette through one type of colour vision. When two swatches in a row look the same, viewers with that deficiency can't tell those colours apart — so never rely on colour alone to carry meaning. Pair it with text, icons, patterns or position.
Simulations use standard dichromat colour matrices — an approximation, not a medical diagnosis, and most people with a deficiency see more colour than the strongest (dichromat) case shown here.
Next door: the WCAG contrast checker. See also accessibility and the accessibility checklist.