Color Blindness Simulator
See how an image or palette looks with common colour vision deficiencies, and which colours become hard to tell apart.
Drop an image
A chart, map, design or photo. See it as people with each type of colour blindness might.
About this tool
See an image the way people with common types of colour blindness might: weak or missing red, green or blue cones, and total colour blindness. View every type side by side, or compare one with the original using a slider, and download the simulations to share with your team.
Check a palette too. Enter the colours of a chart, map or interface, and Interformat lists the pairs that become hard to tell apart for each type, measured in Oklab so the warning matches what eyes notice. Paste a list or a stylesheet to bring in many colours at once.
The simulation uses the Machado, Oliveira and Fernandes (2009) model in linear light, the one used by browser developer tools. It is a simulation, not a diagnosis: it approximates how colours might look, and real perception differs from person to person.
How do I fix colours that clash?
Make them differ in lightness, not only in hue, and don’t rely on colour alone: add labels, patterns, shapes or direct annotations. Palettes like Okabe–Ito are designed to stay distinct.
Why do the "-anomaly" types look milder?
In anomalous trichromacy one type of cone is shifted rather than missing, so colours are confused less. They’re shown at a moderate severity; the "-opia" types show the cone missing entirely.