Color blindness simulator

Preview an image with protanopia, deuteranopia or tritanopia color simulations.

On your device · No account

Privacy details

Color blindness simulator processes your input in this browser. Inputs and results are excluded from analytics. Recent tools save tool names, visit counts and last-visit times. Saved tools store only their names. Draft saving is optional and stays on this device; delete saved text with the draft controls. Loading text from a URL is optional and contacts that server; its URL and your IP address are visible to the server. An optional “Use in” action keeps a handoff in this tab. The next tool removes it on arrival and ignores it if more than a minute has passed.

Copy link includes the inputs you choose to share in the address. Anyone with that link can reopen them. Files and generated results are excluded. Password and key tools share settings only.

Choose an image

Simulation

Your preview

Preparing preview…

Reset reloads the tool with its starting values and releases open files and device controls. Saved drafts stay on this device until you delete them.

Links include your inputs and settings. Anyone with the link can see them, so leave out private text. Files and generated results are left out; random draws run again.

Keyboard shortcuts

Updated 2026-09-19

Using the color blindness simulator

The simulation applies the Machado 2009 full-severity matrices in linear-light sRGB, then converts back to screen RGB. Alpha is preserved. Use it to compare whether a design still communicates through shapes and labels as colors shift.

Next: Color picker from image

A worked example

In the protanopia model, opaque sRGB red #FF0000 becomes approximately #6D5F00 after rounding to byte channels.

Before you use the result

A design approximation, not a vision screening or a prediction of one person’s experience. Out-of-gamut values are clipped. Inputs above two million pixels must be resized first.

Next: Image resizer

Cite this page

Citation style

ToolOctopus. “Color blindness simulator.” Updated 2026-09-19. https://tooloctopus.com/color-blindness-simulator.

Add an access date if your instructions require one.

Citation formatting uses citeproc-js by Frank Bennett and Citation Style Language styles. Licence and source code.