Color Blindness Simulator
Preview how a PNG, JPEG, or WebP image may look to viewers with common colour-vision deficiencies, entirely inside your browser.
Simulation is an approximation for design and accessibility review, not a medical diagnosis. Tritanopia is the least reliable of the four. The exported PNG uses the original resolution and does not keep the original file's metadata.
Browser colour management and display calibration can change how the result looks on your screen.
How to use it
- Select a local PNG, JPEG, or WebP image — it is read in your browser and never uploaded
- Choose a deficiency to simulate: protanopia, deuteranopia, tritanopia, or achromatopsia
- Click Apply simulation and compare the result side by side with the original
- Optionally download the simulated view as a PNG to attach to design or accessibility notes
Load a local image and compare the original side by side with an approximate simulation of protanopia (reduced red sensitivity), deuteranopia (reduced green sensitivity), tritanopia (reduced blue sensitivity), or achromatopsia (no colour, computed from perceptual luminance rather than a flat average of the channels). Each pixel is transformed locally on a canvas; the image is never uploaded, and nothing is stored after you close the tab. The alpha channel is copied through unchanged, so transparent areas stay transparent, and you can export the simulated view as a PNG for design notes or bug reports. Simulation is an approximation for design and accessibility review, not a medical diagnosis, and it cannot detect or measure anyone's vision. Results also depend on your screen: browser colour management and display calibration vary between devices. This tool answers a different question from the WCAG Contrast Checker, which scores the ratio between two specific colours, and from the Image Color Picker, which reads the exact colour value under a single point.
FAQ
It re-colours each pixel of your image to approximate how someone with a given colour-vision deficiency might perceive it, so you can spot information that relies on colour alone.
Protanopia and deuteranopia approximate reduced red and green sensitivity, tritanopia approximates reduced blue sensitivity, and achromatopsia removes colour using perceptual luminance rather than a flat average of the channels.
No. It is an approximation for design and accessibility review, not a medical diagnosis; real colour vision varies between individuals and this tool cannot detect or measure it.
Your original file is never modified. Each simulation starts again from the original pixels, the alpha channel is preserved, and only the PNG you choose to download is a new file.
No. The image is decoded and processed entirely in your browser on a canvas, nothing is sent to a server, and nothing remains after you close or reload the tab.
Browser colour management and display calibration are not identical across devices, so the same simulated image can look slightly different depending on the screen you view it on.