FREE · DESIGN TOOLS
Color Blindness Simulator.
See how images and color palettes appear with protanopia, deuteranopia, tritanopia or achromatopsia, and find color pairs that become hard to tell apart.
100% simulates dichromacy (or achromatopsia); lower values approximate anomalous trichromacy.
PNG, JPG, WebP, GIF (first frame), BMP or AVIF · up to 25 MiB and 25 megapixels.
How to use Color Blindness Simulator
Choose a vision deficiency and severity. Upload, drop or paste a screenshot to compare it with the simulation or view all four types at once, then download the full-resolution PNG. In palette mode, enter HEX colors to see each simulated color and the pairs that fall below the warning threshold.
How it works
Colors are converted to linear sRGB and projected with the Brettel, Viénot and Mollon (1997) dichromat model using the public-domain libDaltonLens matrices. Severities below 100% interpolate between normal and dichromat vision, an approximation of anomalous trichromacy. Achromatopsia uses Rec. 709 luminance. Saturated colors can fall outside sRGB after simulation and are clipped. Confusion warnings compare CIEDE2000 differences before and after simulation; the threshold is a design heuristic. Individual color vision varies, and monitor calibration affects what you see. Transparency is preserved. Images stay in your browser.
Example
A red and green bar chart (#cc3333 and #669933) drops from ΔE2000 61 to about 6 under deuteranopia, so the two series need labels or another contrast cue.
Questions about Color Blindness Simulator
Is Color Blindness Simulator free, and do I need an account?
Yes. This tool is free to use in your browser without an account. Processing takes place on your device.
What are the limits and what should I check?
PNG, JPG, WebP, GIF first frame, BMP or AVIF up to 25 MiB and 25 megapixels; PNG download. Up to 24 HEX colors. A screen-based approximation for typical sRGB displays, not a diagnosis or a vision test. Review the result before using it in your work.
Is my input sent to a server?
Your input is processed in your browser and is not uploaded by this tool. Files and pasted text are cleared when the page is refreshed. Normal website requests are still required to load the page and its libraries. Read the privacy explanation.