Enter hex colours and pick a type of colour blindness; the simulator converts each colour as a viewer with that condition would see it. Pure red #FF0000 with achromatopsia becomes #7F7F7F, a middle grey, because red carries 21% of white's luminance. A table lists all four conditions side by side.
Around 1 in 12 men and 1 in 200 women have some red-green colour deficiency, so a chart legend, status badge or brand palette that relies on red versus green can fail for a real share of readers. This simulator takes a list of hex colours and returns how each one appears with protanopia, deuteranopia, tritanopia and full achromatopsia. It also picks out the two colours in your list that end up closest together for the condition you choose, which is usually the pair to fix first. The conversion uses published matrices for complete loss of one cone type; people with milder anomalous trichromacy see less change than shown here, so treat the output as the worst case for each type.
Type or paste hex codes one per line or comma separated, or open a .txt or .csv file with them.
Choose protanopia, deuteranopia, tritanopia or achromatopsia; the headline and closest pair follow that choice.
Each row gives the original hex and its simulated hex for all four conditions, ready to paste into a design tool.
If the hardest pair has a small distance, change lightness of one colour, not just hue, and check again.
Result First colour as seen: #7F7F7F
Colours checked: 1
Hardest pair to tell apart: —
Their RGB distance (of 441): 0
Red carries only 21% of the luminance of white, so it turns into a middle grey of 127.
Result First colour as seen: #98892E
Colours checked: 4
Hardest pair to tell apart: #E53935 and #43A047
Their RGB distance (of 441): 32
The table shows every colour under all four conditions; the stats name the pair that is hardest to separate.
linear RGB′ = M × linear RGB; achromatopsia: Y = 0.2126 R + 0.7152 G + 0.0722 B
linear RGBMYEach hex colour is decoded to linear light, multiplied by the matrix for the missing cone type, clamped to the 0 to 1 range and re-encoded to sRGB. For achromatopsia only luminance survives, so every colour becomes the grey of equal brightness. The closest pair is the two simulated colours with the smallest straight-line distance in RGB, out of a maximum of 441 between black and white.
Deuteranomaly, a weakened green cone, is the most common, affecting about 5% of men of Northern European descent. Full deuteranopia and protanopia each affect roughly 1% of men. Tritan defects and achromatopsia are rare, well under 1 in 10,000 for the inherited forms.
Without long-wavelength cones, red light is barely registered, so pure red looks dim and shifts toward a brownish yellow. That is why red warning text on black can nearly vanish for protanopes.
It is the straight-line gap between the two simulated colours in RGB space, from 0 for identical colours to about 441 for black against white. Pairs under about 40 tend to be hard to separate, especially in small areas such as chart lines or icons.
Yes. Paste or open a text or CSV file; any token that is a three or six digit hex code is read, and anything else is skipped with a note. Up to 50 colours are processed.
The matrices from Machado, Oliveira and Fernandes, published in IEEE Transactions on Visualization and Computer Graphics in 2009, at full severity. They are applied to linear light, not to gamma-encoded values, which avoids the washed-out results of older shortcut filters.
No. The conversion runs in your browser from the values you type, and nothing is stored after you leave the page.
Using this tool in an assignment, article or report? Copy a citation, or a link for your website.
Tools Directory Editorial Team. (2026, October 23). Color Blindness Simulator. Tools Directory. Retrieved October 26, 2026, from https://tools.milunir.com/design/design-utilities/color-blindness-simulator/
Tools Directory Editorial Team. “Color Blindness Simulator.” Tools Directory, 23 Oct. 2026, https://tools.milunir.com/design/design-utilities/color-blindness-simulator/. Accessed 26 Oct. 2026.
Tools Directory Editorial Team. “Color Blindness Simulator.” Tools Directory. Last modified October 23, 2026. Accessed October 26, 2026. https://tools.milunir.com/design/design-utilities/color-blindness-simulator/.
<a href="https://tools.milunir.com/design/design-utilities/color-blindness-simulator/">Color Blindness Simulator – Tools Directory</a>