Classic red-green screening
Read the numbers hidden in colored dots to check for red-green color vision differences. This online self-check is not a diagnosis.
Short answer
The Ishihara test is the classic red-green color blindness screening: you read numbers hidden in plates of colored dots. This free online version screens for red-green color vision deficiency and estimates the type (protan or deutan) in about a minute, with freshly generated plates each time so answers can't be memorized.
Screening is reliable on a normal screen; the type is best read as an estimate. The Ishihara test checks red-green vision only — it does not test blue-yellow (tritan).
Each plate is a circle of colored dots with a number hidden inside it. People with typical color vision see the number easily; people with a red-green deficiency see a different number or none at all. You'll see 13 plates, including one demonstration plate everyone can read.
Tap the number you read (or 'Nothing' if no figure stands out). Don't strain or tilt your head — answer with the first thing you see. The plates are pseudo-isochromatic: the figure and background match in brightness, so only color tells them apart.
We count which plates you missed. Misses concentrated on the red axis suggest protan (red-weak); on the green axis, deutan (green-weak). How many you miss estimates the severity. Because your screen isn't calibrated, treat the type and severity as estimates, not a diagnosis.
Because not every plate is meant to be readable. Ishihara plates come in five categories, and two of them are designed so that seeing nothing is the correct outcome — on a hidden-digit plate, reading the number is the sign of a deficiency. This is the single most misread part of the test: people fail a plate they were never supposed to pass, or pass one that should have been blank.
Does it find red-green deficiency? Yes — on a normal screen this is reliable screening for the protan and deutan types.
Which of the two is it? A strong hint: protan (red-weak) or deutan (green-weak). Mild cases sit close together, so treat the type as an estimate.
What about blue-yellow? Ishihara plates don't test tritan at all. For that, take the full color vision test.
Using it for a licence or job? Have it confirmed by an eye-care professional before it counts for anything official.
This is a free screening and self-assessment tool, not a medical diagnosis. Results are affected by your screen, its color settings, and room lighting.
There is no single Ishihara test — the book ships in several editions, and which one you meet depends on where you are being tested. The full clinical book has 38 plates; most eye clinics keep the 24-plate concise edition; pre-employment and school screenings usually run the 14-plate abbreviated set.
Less evenly than its reputation suggests. Ishihara is named in law for Filipino seafarers and used routinely on India's driving-licence medical — but it is not part of UK licensing at all, and the FAA dropped printed plates for new pilot applicants in 2025. Where a real decision rides on your colour vision, what matters is which test that authority accepts.
You can memorize a printed Ishihara book, and people do — the plate order is fixed and the answers circulate freely online. This is a real problem for pre-employment and licensing medicals, and it is why clinics shuffle plate order, cover the plate number, and re-test with different equipment when a result looks rehearsed.
It does not work on this page. The plates here are generated from a random seed at the start of every session, so the hidden digits and the dot pattern are different each time — there is no answer key to look up. The underlying science is unchanged: dots are matched in brightness so that only the red-green signal separates figure from background.
Worth saying plainly: passing a memorized test does not change your color vision. Where a color vision standard exists it usually exists for a safety reason, and safety-critical roles re-test with an anomaloscope or a CAD test, which cannot be memorized at all. Knowing your real result before the medical is the more useful position to be in.
For the question most people are actually asking — do I have a red-green color vision deficiency? — an online Ishihara test on an ordinary uncalibrated screen agrees closely with the printed plates. Screening is a coarse yes/no judgement, and the red-green separation the plates rely on survives the colour error a typical laptop or phone introduces.
Two things degrade on a screen. Type (protan vs deutan) is an estimate: mild cases sit close together on the confusion axes, and screen error is large enough to push a borderline reader across the line. Severity is relative, not absolute — it tells you where you sit against other people taking the same test, not a clinical grade.
Three conditions matter more than the device: full screen brightness, night-shift and blue-light filters off, and a room that is not brightly lit. A missed demonstration plate is the tell that one of these is wrong, which is why this test refuses to score a run where the demonstration plate was misread.
Ishihara is the fastest way to answer “do I have a red-green deficiency?” — and it is the wrong tool for every other question. It cannot see the blue-yellow axis, and it grades severity only coarsely. If the Ishihara result raised a question it can't settle, this is where to go next.
The Ishihara test is a color vision screening developed by Dr. Shinobu Ishihara in 1917. It uses pseudo-isochromatic plates — circles of colored dots with a number hidden inside — to screen for red-green color blindness. It is the most widely used color blindness test in the world.
The Ishihara test is one kind of colour blind test — the classic one, and the one most people mean by a "color blind number test" because its plates hide numbers in coloured dots. "Colour blind test" (British spelling), "test Ishihara", "Ishihara plate test" and "daltonism test" all lead to the same red-green screening. Note that a full colour blind test can also check blue-yellow, which the Ishihara plates never do.
For screening — telling whether you likely have a red-green color vision deficiency — an online Ishihara test on a normal screen agrees closely with clinical screening. Identifying the exact type (protan vs deutan) and severity is less reliable on an uncalibrated screen and should be treated as an estimate.
No. The Ishihara test screens red-green deficiencies only (protan and deutan). It does not detect blue-yellow (tritan) deficiency. For a blue-yellow check, use our full color vision test, which includes the blue cone.
The full clinical Ishihara book has 38 plates, with shorter 24-plate and 14-plate editions used for quick screening. This online version uses 13 plates — one demonstration plate plus a balanced set of red-green plates — which is enough to screen reliably while staying short.
The original 38-plate plates are copyrighted, and the PDFs floating around online are usually low-quality scans. Printing or viewing them can shift the colors, which is exactly what the test depends on, so a downloaded PDF often gives a misleading result. This free online Ishihara test uses fresh, brightness-matched plates for screening, with no download needed.
The official book is published as Ishihara's Tests for Colour Deficiency and sold by medical-supply and ophthalmology publishers, in the 38-, 24- and 14-plate editions. It is the printed gold standard clinics use, and the right choice if you need a certified physical test. For a quick self-check, this free online version uses the same pseudo-isochromatic method without the cost. Only an eye-care professional's test counts for licensing or a job.
To stop people from memorizing answers, our plates are generated fresh from a random seed every session, so the hidden numbers and dot patterns change each time. The science (pseudo-isochromatic, brightness-matched dots) is identical to the printed Ishihara plates.
Use it for self-screening only. For licensing, aviation, or any medical or employment decision, confirm your result with an eye-care professional using clinical equipment (such as an anomaloscope or CAD test).
Any optometrist, ophthalmology clinic, or occupational-health center that does eye exams can administer the printed Ishihara test — it is standard equipment. In countries where color vision is part of pre-employment or licensing medicals, such as the Philippines and India, the clinics that run those medical packages all offer it. A practical route: take this free online screening first, so you walk in knowing whether a deficiency is likely and which type — then have the clinic confirm it on the printed plates.
At a clinic it is usually either included in a standard eye exam or a pre-employment medical package, or charged as a small add-on — prices vary widely by country and clinic, so ask when booking. The online screening on this page is free, with no sign-up; the difference you are paying for at a clinic is calibrated printed plates and a professional result that counts for official purposes.
Full color vision test
All three axes, including the blue-yellow one Ishihara plates never touch.
Protan vs deutan
What separates red-weak from green-weak, and why plates can't always tell.
Ishihara test for kids
The same science with shapes and paths instead of numbers, for pre-readers.
Driving licence rules by country
Where a colour vision result actually affects licensing, sourced per country.
Last reviewed September 2, 2026. Informational only and regularly reviewed — not a substitute for advice from an eye-care professional.