Color Blindness Simulator

How to use Color Blindness Simulator

1. Open Color Blindness Simulator — it runs entirely in your browser with no setup.
2. Paste or type your input into the text area, or upload a file where supported.
3. Set any options you need. The result appears in the output panel — there is no upload step and no waiting on a server.
4. Review the output instantly; large inputs are handled locally without lag.
5. Copy the result to your clipboard or download it. Your data never leaves the page.

Why use Color Blindness Simulator?

• 100% free with no limits, no sign-up and no watermarks.
• Private by design — your data are processed in your browser and never uploaded to a server.
• Fast and lightweight, with instant results even on a phone or a slow connection.
• Works everywhere — any modern browser on Windows, macOS, Linux, Android or iOS.
• Part of a full color tools suite, so related color blindness simulator tasks are one click away.

What people use Color Blindness Simulator for

• Checking whether a chart remains readable to colour-blind viewers.
• Testing whether a red/green status indicator is distinguishable.
• Validating a palette for accessibility before shipping.

Color Blindness Simulator: limits and things worth knowing

• Around 8% of men and 0.5% of women of northern European descent have some colour vision deficiency, so this affects a substantial share of any general audience.
• Deuteranomaly, reduced green sensitivity, is by far the most common form. Protanopia and tritanopia are rarer, and full monochromacy is very rare.
• Red and green status indicators are the classic failure. The fix is not a different palette but a second channel — shape, icon, label or position — because colour alone should never carry meaning.
• WCAG 1.4.1 requires exactly that: information must not be conveyed by colour alone.
• Simulations approximate the experience; they are a design check, not a clinical model.

Sources

• WCAG 2.2 — Use of Color 1.4.1

Is it private and secure?

Your privacy is built in. Color Blindness Simulator runs completely on your device, so whatever you enter stays in your browser and is never transmitted, logged or stored on any server.

Network activity: none. Nothing is sent and nothing is fetched. This tool makes no network request at all once the page has loaded — which is why it keeps working if your connection drops.

You do not have to take that on trust — our privacy proof page publishes the Content-Security-Policy that enforces it, lists every third party it permits, and shows how to verify the whole claim yourself.

Learn more

Why Browser-Based Tools Are Safer for Your Files — Most online converters upload your files to a server. Client-side tools don't. Here's why that difference matters for privacy.