Color Blindness Test
Look at each circle of dots and type the number you see, or choose “I can't see a number”. The 14 plates are drawn fresh for every test and take about two minutes. This is a screening tool, not a medical diagnosis.
Before you start
- Set your screen to full brightness.
- Turn off Night Light, Night Shift, True Tone, blue light filters and dark mode extensions.
- Sit about an arm's length from the screen, in normal room light.
- Answer within about 3 seconds per plate. If you see no number, say so.
The sample plate shows 12. Everyone should see it. There are 14 plates and they change every time you take the test.
Keyboard: type digits, Enter for next, N for no number.
Review your answers
This online test is a screening aid only and cannot diagnose color vision deficiency. Screen color settings affect results. For a diagnosis, see an optometrist or eye doctor.
How to use the Color Blindness Test
- Prepare your screen: full brightness, and turn off Night Light, Night Shift, True Tone, blue light filters and dark-reader extensions.
- Press Start test and view the plate from about arm's length.
- Type the number you see (or tap the keypad) and press Next. Answer within a few seconds; do not stare.
- Choose “I can't see a number” when you see no number. Some plates may show nothing to you; that is part of the test.
- Read your result and review every plate. If it suggests a deficiency, book a professional eye test to confirm.
How the plates are made
Human color vision uses three cone types, sensitive to long (L, red), medium (M, green) and short (S, blue) wavelengths. Each plate converts its colors to cone signals using the standard sRGB to LMS model of Viénot, Brettel and Mollon (1999) and then changes only one cone signal between the number and the background:
- Protan plates change only the L-cone signal. Someone without working L cones sees no difference at all.
- Deutan plates change only the M-cone signal, which people without working M cones cannot see.
- Tritan plates change only the S-cone signal and test blue-yellow vision.
- Classification plates draw one digit with an L-only change and the other with an M-only change, so protan and deutan viewers each tend to read a different single digit.
Every dot also gets a random brightness, so the number cannot be found by lightness, only by color. Plates come in strong, medium and subtle versions to catch milder color weakness. Because screens are not calibrated like printed test plates, treat the result as a screening hint.
Types of color vision deficiency
| Type | Cone affected | Colors often confused |
|---|---|---|
| Protanomaly / protanopia | L (red) | Red with green and brown; reds look darker |
| Deuteranomaly / deuteranopia | M (green) | Green with red, beige and brown; the most common form |
| Tritanomaly / tritanopia | S (blue) | Blue with green, yellow with pink or violet; rare |
| Achromatopsia | All cones | Sees mostly shades of grey; very rare |
The "-anomaly" forms mean the cone works but with shifted sensitivity (milder), while "-anopia" means the cone type is missing. Red-green deficiencies are usually inherited on the X chromosome, which is why they are far more common in men.
Living with color blindness
- Phones and computers have color filters for color blindness in their accessibility settings.
- Use labels, patterns and positions, not color alone, in charts, maps and wiring.
- See how images look to people with different types using the color blindness simulator.
- Some jobs, such as pilot, electrician or train driver, have color vision requirements; ask for a professional assessment early.
Frequently asked questions
How does this color blindness test work?
Each plate is a circle of dots. The dots that form the number differ from the background only in color, along the lines of colors that people with a specific color vision deficiency cannot tell apart. Dot brightness is randomised so lightness gives no clue. People with normal color vision see the numbers; people with a deficiency see some of them faintly or not at all.
Is this the real Ishihara test?
No. The original Ishihara plates are copyrighted printed plates used under controlled lighting. This test uses the same principle with plates generated on your screen, so it is a quick screening check. Screens differ in color accuracy, which is why a professional test is needed for a diagnosis.
What is the difference between protan, deutan and tritan?
They refer to which of the three cone types in the eye is missing or altered. Protan affects the long-wavelength (red) cones, deutan the medium-wavelength (green) cones, and both cause red-green confusion. Tritan affects the short-wavelength (blue) cones and causes blue-yellow confusion; it is much rarer.
How common is color blindness?
Red-green color vision deficiency affects about 1 in 12 men (8%) and about 1 in 200 women (0.5%) of Northern European ancestry, and is less common in some other populations. Deutan types are the most common. Tritan deficiency is rare, at roughly 1 in 10,000 people or fewer.
Can my screen affect the result?
Yes. Night modes and blue light filters shift colors toward yellow and can make blue-yellow plates very hard to see, and low-quality or badly calibrated screens can weaken red-green plates. Use full brightness, turn color filters off and, if possible, repeat the test on a second device.
What should I do if the test says I may be color blind?
Repeat it on another screen, then see an optometrist or eye doctor. They can confirm the type and degree with standardised plates or an anomaloscope. Color vision deficiency cannot usually be cured, but knowing about it helps at school and work, and color-correcting glasses or phone accessibility filters help some people.
Can children take this test?
Children who know their numbers can try it with an adult, but they may guess or lose concentration, so results are less reliable. Eye care professionals use special plates with shapes and paths for young children.