Simulate an image
Is your palette colorblind-safe?
Paste colors separated by commas or new lines.
Original
Protanopia distinguishable
Deuteranopia distinguishable
Tritanopia distinguishable
Achromatopsia 1 collision
#e63946 ↔ #2a9d8f look nearly identical — adjust lightness.
How to use
01
Upload a design or photo
We render it through protanopia, deuteranopia, tritanopia, and achromatopsia simulations, side by side with the original.
02
Or test your brand palette
Paste your colors and we flag pairs that become indistinguishable under each vision type.
03
Fix the collisions
Adjust lightness, not just hue: colors that differ in brightness stay distinguishable for everyone.
Why Color Blindness Simulator
- About 8% of men and 0.5% of women have some form of color vision deficiency.
- Four medically-modeled simulations: protanopia, deuteranopia, tritanopia, achromatopsia.
- Palette mode flags exact color pairs that collide under each vision type.
- Everything runs in your browser, images are never uploaded.
Common questions
How accurate are the simulations?
We use the widely-adopted Viénot/Brettel transformation matrices, the same approach used by Chrome DevTools and most design tools. They model full dichromacy (the strongest form); real-world deficiency is often milder.
What does WCAG say about color blindness?
Criterion 1.4.1 (Use of Color, Level A) requires that color is never the only way to convey information — pair color with icons, labels, or patterns. Criterion 1.4.3 contrast requirements also help, since adequate luminance contrast survives color vision deficiency.
How do I fix a colliding palette?
Vary lightness, not just hue: a light yellow-green and a dark blue-green stay distinguishable even when their hues collapse. Our palette test shows which pairs collide so you know exactly what to adjust.
Is Color Blindness Simulator free to use?
Yes. Color Blindness Simulator is completely free. There is no sign up, no trial, and no usage cap.
Do I need an account to use Color Blindness Simulator?
No. You can start using Color Blindness Simulator straight away. We do not ask for an email address or a login.
Is my data uploaded to a server when I use Color Blindness Simulator?
No. Color Blindness Simulator runs entirely inside your browser, so the input you enter never leaves your device and nothing is sent to us.
Do you store the input I use with Color Blindness Simulator?
No. Because everything happens locally in your browser, there is nothing for us to store. Close the tab and it is gone.
How do I use Color Blindness Simulator?
Enter or paste your input and Color Blindness Simulator updates the result as you go. When it looks right, copy or download it with one click.
Does Color Blindness Simulator work on phones and tablets?
Yes. Color Blindness Simulator is responsive and works in any modern browser on mobile, tablet, and desktop.
Which browsers does Color Blindness Simulator support?
It works in current versions of Chrome, Firefox, Safari, and Edge. For the best experience, keep your browser up to date.
Is there a limit on how often I can use Color Blindness Simulator?
No. You can use Color Blindness Simulator as many times as you need, at no cost.
Can I use Color Blindness Simulator for commercial or client work?
Yes. You are free to use the output in personal, educational, and commercial projects.
Why is Color Blindness Simulator free?
The site is supported by advertising, which lets us keep every tool free and open to everyone.
What should I do if Color Blindness Simulator gives an unexpected result?
First check that your input is formatted as expected. If something still looks wrong, use the feedback link on the page and we will take a look.
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