Color Blind Test
A free, Ishihara-style screening test for colour vision deficiency. Read the number hidden in each plate of coloured dots — eight plates, about a minute. Nothing is uploaded and no signup is required.
Plate 1 of 8
View at 100% zoom in normal lighting. Screenshots, filters, night-shift modes and uncalibrated displays all change the result.
How the test works
Each plate is filled with dots of varying size and shade. A digit is drawn into the pattern using dots whose colour differs from the background mainly in hue, while keeping lightness roughly equal. That matters: if the digit were simply darker, everyone could read it by brightness alone and the plate would test nothing.
The red-green plates use warm orange-red figures against olive-green backgrounds — the pair that protan and deutan deficiencies confuse. The blue-yellow plates use pink-violet against teal. The first plate is a high-contrast control that nearly everyone can read; missing it usually signals a display or zoom problem rather than colour vision.
Types of colour vision deficiency
Deuteranomaly / deuteranopia — reduced or absent green cone function. The most common form, and the reason red-green confusion dominates the statistics.
Protanomaly / protanopia — reduced or absent red cone function. Reds also appear noticeably darker than they do to typical viewers.
Tritanomaly / tritanopia — reduced or absent blue cone function. Rare, and affects blue-yellow discrimination rather than red-green.
Achromatopsia — no colour perception at all. Very rare, and usually accompanied by light sensitivity and reduced acuity.
Designing for colour vision deficiency
Around 8% of men have a red-green deficiency, so any interface that relies on colour alone will fail a meaningful share of its users. The fix is straightforward: never encode meaning in hue by itself. Pair colour with text, icons, patterns or position — a red error state should also say “error”, and a green success state should also carry a tick.
Keep sufficient lightness contrast as well as hue contrast, since lightness survives every type of deficiency. WCAG 2.1 requires 4.5:1 for normal text and 3:1 for large text — check pairings with the contrast checker, and preview your palette with the colour blindness simulator to see how it reads to others.
Frequently asked questions
What is a color blind test?
A color blind test screens for color vision deficiency using plates covered in coloured dots. A number is hidden in the dot pattern using colours that differ mainly in hue rather than brightness, so people with typical colour vision can read it while those with a deficiency cannot. The best-known version is the Ishihara test, developed by Dr Shinobu Ishihara in 1917.
How accurate is an online color blind test?
An online test is a screening tool, not a diagnosis. Screen calibration, brightness, ambient lighting, blue-light filters and image scaling all shift the colours you actually see, so results vary between devices. A clinical test uses printed plates under standardised lighting. Use an online test to decide whether to get checked properly — not as a final answer.
What are the types of color blindness?
The most common is red-green deficiency, split into protanopia/protanomaly (reduced or absent red cone response) and deuteranopia/deuteranomaly (green cones). Blue-yellow deficiency, called tritanopia or tritanomaly, is much rarer. Complete colour blindness, achromatopsia, where no colour is perceived at all, is very rare.
How common is color blindness?
Red-green colour vision deficiency affects roughly 1 in 12 men (about 8%) and 1 in 200 women (about 0.5%). The difference is because the genes for red and green cone pigments sit on the X chromosome. Blue-yellow deficiency is far rarer and affects men and women about equally.
Can color blindness be cured?
Inherited colour vision deficiency cannot currently be cured — it is caused by the cone photoreceptors in the retina. Some tinted lenses increase the perceived separation between confusable colours, which helps some people distinguish them, but they do not restore normal colour vision. Colour vision loss that appears suddenly in adulthood can indicate another condition and should be checked by a doctor.
What should I do if this test suggests I am color blind?
See an optometrist or ophthalmologist. They can confirm the result with clinical plates and, if needed, an anomaloscope, which identifies the exact type and severity. A formal assessment matters if you need colour vision certification for work such as aviation, rail, marine, electrical or some armed forces roles.