Color Blind Simulator
See how any colour appears to people with 8 types of colour vision deficiency (CVD) - protanopia, deuteranopia, tritanopia, protanomaly, deuteranomaly, tritanomaly, achromatopsia, and achromatomaly. Enter a HEX colour and instantly compare all CVD types side-by-side with normal vision. Click any type for a detailed description, prevalence statistics, and exact simulated RGB values. Fully private, 100% free, and no signup required.
Sample Colors
How This Colour Looks Under Each CVD Type
Color Vision Deficiency Quick Reference
Why Use Our Color Blind Simulator?
Instant CVD Simulation
The colour blind simulator transforms any colour instantly on every keystroke - no button to press. See how a colour appears under all 8 types of colour vision deficiency simultaneously with real-time swatch updates.
8 CVD Types Supported
The colour blind simulator covers all major colour vision deficiency types: protanopia, deuteranopia, tritanopia, protanomaly, deuteranomaly, tritanomaly, achromatopsia, and achromatomaly. Each type includes a description and prevalence statistics.
100% Private - No Upload
All simulation happens locally in your browser using scientifically validated transformation matrices. Your colour values never leave your device and are never sent to any server.
Free & No Limits
Simulate unlimited colours with no signup, no subscription, and no usage caps. The colour blind simulator is completely free forever with no ads blocking the interface.
Common Use Cases for Color Blind Simulator
Web Accessibility Compliance
Web developers use the colour blind simulator to check that UI elements, charts, and data visualisations remain usable for users with colour vision deficiencies, helping meet WCAG 2.1 Success Criterion 1.4.1 (Use of Color).
UI Design for Accessibility
UI/UX designers use the colour blind simulator to test colour palettes and ensure that information is not conveyed by colour alone. This helps create interfaces that are accessible to the ~300 million people worldwide with CVD.
Accessibility Auditing
Accessibility auditors use the colour blind simulator to evaluate existing designs and identify problem areas where colour-dependent information might be lost for users with different types of colour vision deficiency.
Data Visualisation Testing
Data scientists and information designers use the colour blind simulator to verify that charts, graphs, and maps remain interpretable under all common types of colour blindness, ensuring their data reaches the widest audience.
Game & App Development
Game and app developers use the colour blind simulator to test UI elements, indicators, and colour-coded gameplay mechanics, ensuring their products are accessible to players with colour vision deficiencies.
Education & Awareness
Educators and students use the colour blind simulator to understand how colour vision deficiencies affect perception, raising awareness about accessibility and the importance of inclusive design practices.
Understanding Color Vision Deficiency
What is Color Vision Deficiency?
Colour vision deficiency (CVD), commonly called colour blindness, is a reduced ability to distinguish between certain colours. It occurs when one or more of the three types of cone cells in the retina - L (red), M (green), and S (blue) - are missing, dysfunctional, or have altered spectral sensitivity. The most common forms affect red-green discrimination and affect approximately 8% of males and 0.5% of females worldwide. Our colour blind simulator uses the Brettel-Viénot-Mollon model to accurately simulate how colours appear under each type of CVD.
How Our Color Blind Simulator Works
- Enter a colour: Type a HEX value (e.g.
#FF0000), use the native colour picker, or click a sample colour. The tool converts the HEX to RGB and prepares it for simulation. - Apply CVD transformations: The colour is first converted from sRGB to linear light space. Then a 3×3 transformation matrix specific to each CVD type is applied, simulating how the absent or altered cone would affect perception. The result is converted back to sRGB for display.
- Compare side-by-side: All 9 vision types are shown in a grid - including normal vision as a reference. Click any CVD type to see a detailed description, prevalence statistics, and the exact RGB values of the simulated colour.
Types of Color Vision Deficiency
- Protanopia & Protanomaly: Red cone (L-cone) deficiency. Protanopia is a complete absence, while protanomaly is reduced sensitivity. Reds appear darker and red-green discrimination is impaired. Affects ~2% of males.
- Deuteranopia & Deuteranomaly: Green cone (M-cone) deficiency. Deuteranomaly is the most common CVD overall (~5% of males). Green discrimination is reduced and the world appears shifted towards yellow-blue.
- Tritanopia & Tritanomaly: Blue cone (S-cone) deficiency. Extremely rare (~0.01% of population). Blue-yellow discrimination is lost. Unlike red-green CVDs, tritan defects affect males and females equally.
- Achromatopsia & Achromatomaly: Complete or partial absence of all cone function. The world appears in shades of grey. Very rare (~0.003% of population).
CVD Simulation Accuracy & Limitations
Our colour blind simulator uses the computational model published by Bretell, Viénot and Mollon (1997), refined by Machado (2009), applied in linear sRGB space. This is the same model used by industry-standard tools like Adobe Photoshop, Colour Oracle, and Chrome DevTools. The simulation shows how a colour would appear to a person with dichromatic or anomalous trichromatic vision under ideal viewing conditions.
Important limitations: Real CVD perception varies between individuals - severity, lighting conditions, and display calibration all affect actual perception. The simulation is an approximation that represents the average or typical experience. Always test designs with real users when possible, and never rely solely on colour as the only means of conveying information.
Related Accessibility Tools
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Calculate WCAG 2.1 contrast ratio and check AA/AAA compliance for normal text, large text, and UI components.
Color Inverter
Invert any colour to get its exact opposite instantly with side-by-side preview and complementary relationship indicator.
Color Picker & Converter
Visual colour picker with HEX ↔ RGB ↔ HSL ↔ HSV ↔ CMYK ↔ HWB ↔ CIE LAB conversion and WCAG contrast checker.
HEX to RGB Converter
Convert any HEX colour code to RGB and RGBA values instantly. Supports all HEX formats including alpha transparency.
Frequently Asked Questions About Color Blind Simulator
A colour blind simulator transforms colours to show how they appear to people with different types of colour vision deficiency (CVD). Our simulator uses the scientifically validated Brettel-Viénot-Mollon model to simulate 8 CVD types + normal vision simultaneously. Enter any HEX colour and see how it looks under each type in real time.
The simulation uses 3×3 transformation matrices applied in linear sRGB space, based on the Brettel-Viénot-Mollon (1997) model refined by Machado (2009). This is the same model used by Adobe Photoshop, Colour Oracle, and Chrome DevTools. However, CVD perception varies between individuals due to severity, lighting, and display differences - the simulation represents a typical approximation, not an exact depiction for every individual.
The colour blind simulator supports 8 types: protanopia (no red cones), deuteranopia (no green cones), tritanopia (no blue cones), protanomaly (reduced red sensitivity), deuteranomaly (reduced green sensitivity), tritanomaly (reduced blue sensitivity), achromatopsia (complete colour blindness), and achromatomaly (partial colour blindness). Normal vision is also shown as a reference.
Colour vision deficiency affects approximately 8% of males and 0.5% of females worldwide - roughly 300 million people. Deuteranomaly (reduced green sensitivity) is the most common type at ~5% of males. Deuteranopia and protanopia each affect ~1% of males. Tritanopia and achromatopsia are extremely rare, affecting less than 0.01% of the population.
Yes. All simulation happens 100% client-side in your browser using JavaScript. Your colour values are never sent to any server, never stored, and never transmitted anywhere. The colour blind simulator is completely private.
Use the simulator to test colour combinations in your designs. If two colours look identical under a particular CVD type, consider using additional visual cues like icons, patterns, labels, or text in addition to colour. WCAG 2.1 Success Criterion 1.4.1 requires that colour is not the only way information is conveyed.
Yes. The colour blind simulator is 100% free with no signup required, no premium features, and no usage limits. Simulate unlimited colours without any restrictions or hidden costs.
The suffix "-opia" (as in protanopia) means a complete absence of that cone type - the person has no functional cones of that type. "-omaly" (as in protanomaly) means the cones are present but have reduced sensitivity or abnormal spectral response. -opia conditions are more severe, while -omaly conditions are milder and more common.