Which algorithm does the simulator use?

It uses the Machado et al. (2009) sRGB transformation matrices at full severity — the same approach used by Chrome DevTools. Colours are gamma-decoded to linear RGB, multiplied by the deficiency matrix, then gamma-encoded back to sRGB.

Is my colour data uploaded?

No. All simulation maths happens locally in your browser. Nothing about the colour you enter is sent to any server.

How accurate is the simulation?

It is a well-established scientific approximation suitable for design and accessibility checks, but it is not a medical diagnosis. Colour vision varies between individuals, so use it as guidance, not a definitive test.

Color Blindness Simulator

See how a colour looks with protanopia, deuteranopia and tritanopia.

Colour blindness simulator

Enter any colour and see how it appears to people with the most common colour vision deficiencies: protanopia, deuteranopia, tritanopia and full achromatopsia.

The simulation uses the standard Machado (2009) sRGB matrices at full severity — the same method used by browser dev tools. It is an approximation for design and accessibility work, not a medical diagnosis. All processing happens locally in your browser; nothing is uploaded.