How accurate is the simulation?

The model is based on research into the eye's cone cells and is the standard approach in design and accessibility work. It shows colour confusion well, though individual colour vision varies, so treat it as a close approximation.

My colours are a problem — how do I fix them?

Don't rely on colour alone: add patterns, labels or shape differences, and choose colours with strong brightness contrast. Blue and orange are usually easier to tell apart than red and green.

Are my files uploaded?

No. Everything runs locally in your browser with no network upload, and is discarded when you close the page.

Do I need to sign up or pay?

No. The site is completely free, needs no account, has no usage limits and adds no watermark.

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👁️Color Blindness Simulator - See Images as Color-Blind People Do

Roughly 1 in 12 men has some form of colour vision deficiency, most often red-green. If a chart separates data only by red and green, or a map uses similar hues for different regions, these viewers may not see the difference at all. This tool uses the widely cited Machado et al. (2009) model in linear RGB to simulate protanopia, deuteranopia, tritanopia and achromatopsia; lowering the severity simulates the more common anomalous trichromacy. By default it produces one comparison image showing normal vision alongside all four types, so you can check at a glance whether a design works for everyone.

Free · No sign-up · Runs in your browserLast updated: 2026-10-26

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How to use Color Blindness Simulator

1Drop in designs, charts or photos
2Choose a comparison of all types or a single type, and adjust severity
3Click Simulate, then review and download

FAQ

How accurate is the simulation?: The model is based on research into the eye's cone cells and is the standard approach in design and accessibility work. It shows colour confusion well, though individual colour vision varies, so treat it as a close approximation.
My colours are a problem — how do I fix them?: Don't rely on colour alone: add patterns, labels or shape differences, and choose colours with strong brightness contrast. Blue and orange are usually easier to tell apart than red and green.
Are my files uploaded?: No. Everything runs locally in your browser with no network upload, and is discarded when you close the page.
Do I need to sign up or pay?: No. The site is completely free, needs no account, has no usage limits and adds no watermark.