Tool · Color blindness simulator

Color blindness simulator.

Paste any palette - see it through all four color vision deficiency types. Catch palette pairs that collapse to the same color for ~5% of your audience.

Paste a palette (any format, comma or space separated)

Adjust:

Normal vision

What most people see

Protanopia

Red-blind (~1.3% of men)

Protanomaly

Red-weak (~1.3% of men)

Deuteranopia

Green-blind (~1.2% of men)

Deuteranomaly

Green-weak (~5% of men - the most common CVD)

Tritanopia

Blue-blind (rare)

Tritanomaly

Blue-weak (rare)

Achromatopsia

No color vision (very rare)

#A7C4BCand#F2B845become indistinguishable under achromatopsia (simulated ΔE 0.8)

Achromatomaly

Partial color loss (very rare)

About these simulations → Uses standard SVG color matrix transforms approximating Brettel's published CVD models. Approximate but well-aligned with research-grade simulators. For production sign-off, validate with people who actually have CVD.

What is the color blindness simulator?

A color blindness simulator shows how an image or palette looks to people with color vision deficiency: protanopia and deuteranopia (red-green, the most common), tritanopia (blue-yellow) and achromatopsia (no color), plus the milder anomalous forms.

How the simulation works

Colors are converted to LMS cone response space and the affected cone's signal is projected onto the remaining two, using the Machado, Oliveira and Fernandes model, which is the standard for simulating dichromacy and adjustable-severity anomalies. Upload a design, a chart or a photo, or paste a palette, and view all eight conditions side by side. About 8 percent of men and 0.5 percent of women have some form of color vision deficiency, so a chart that relies on red versus green alone fails a meaningful share of readers.

Making a palette colorblind safe

The tool flags palette pairs that become indistinguishable under each condition and suggests replacements that keep the brand hue where possible. Rules that help: vary lightness as well as hue, avoid red next to green and blue next to purple as the only difference, and add shape, labels or pattern to charts. The gradient palette tool applies the same check to data scales.

Color Blindness Simulator FAQ

What do color blind people see?

It depends on the type. Deuteranopia and protanopia merge reds, greens, oranges and browns; tritanopia merges blues with greens and yellows with pinks; achromatopsia removes hue entirely. The simulator shows each.

How do I check if my design is colorblind friendly?

Upload it here and step through the conditions. Anything that relies on hue alone to carry meaning will show up as ambiguous.

Is there a color blind test on this site?

This tool simulates color vision deficiency for designers. A screening test with Ishihara-style plates is a separate tool; see the related links.

Which colors are safe for color blindness?

Blue and orange, blue and red, and any pair that differs strongly in lightness are safe for the common red-green types. The tool checks any pair you enter.