Color Blindness Sim

Color Blindness Sim is a free color & design tool that runs entirely in your browser — preview palettes under CVD types. No upload, no account, no limits.

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How to use Color Blindness Sim

Open the Color Blindness Sim tool.
Paste or type your color value into the input field.
The output updates as you type — adjust the options if you need a different format.
Copy the result, or share the URL to hand the exact input to someone else.

About Color Blindness Sim

Preview how a color and a reference palette appear under different types of color blindness — protanopia, deuteranopia, tritanopia and achromatopsia — side by side with normal vision. A quick accessibility sanity check for UI palettes.

It's an approximation for design review, not a medical diagnostic tool.

What people use it for

Check whether your status colors stay distinguishable for color-blind users.
Review a palette across common CVD types before shipping.

Frequently asked questions

Which vision types are simulated?

Protanopia, deuteranopia, tritanopia and achromatopsia, alongside normal vision.

Is it medically accurate?

No — it's a simulation for design review, useful but approximate.

Is it private?

Every calculation happens on this page, in your own browser. Your input is never sent to a server, never logged and never used for training — which also means the tool keeps working when you are offline.