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Detect Color Blindness

Ishihara Test. Online

The classic dotted-plate colour-vision test, online and free. Read the number hidden in each plate.

Plate 1 of 14

What number do you see?

No timer · answers stay on your device

Tip: view in good lighting at 100% screen brightness for the most reliable result.

Not a medical diagnosis. This is an educational screening tool, not a clinical exam. Screen brightness, colour settings and lighting all affect the result. For anything that matters, a driving or aviation medical, a job requirement, or a health concern, book a professional colour-vision test with an optometrist or ophthalmologist.

What is the Ishihara test?

The Ishihara test is the best-known screening method for colour vision deficiency, published by Dr. Shinobu Ishihara in 1917. Each plate is a mosaic of coloured dots with a number, or a winding path, hidden inside. The dots are chosen so that people with typical colour vision and people with a red-green deficiency read the plate differently: some numbers are visible to one group and not the other.

How it's used

The full clinical booklet has 38 plates, including "transformation" and "vanishing" designs and a set of classification plates that help separate protan from deutan types. Shorter 14- and 24-plate versions are common for quick screening. This online version uses original, Ishihara-style plates generated for the web, the published plates are copyrighted, so we don't reproduce them, but the underlying principle is the same.

Accuracy and limits

Ishihara plates are excellent at flagging red-green deficiency and poor at blue-yellow. On a screen, brightness and colour calibration matter a great deal. For a definitive diagnosis and classification, clinicians combine plates with an anomaloscope or the Farnsworth D-15 arrangement test.

Related: full color blind test · red-green test · types of colour blindness.

Frequently asked questions

What is the Ishihara test?
It's the classic colour-vision screening method, introduced by Dr. Shinobu Ishihara in 1917. Numbers or paths are hidden in a field of coloured dots so that people with normal vision and people with colour deficiency see them differently.
How many plates are in the full Ishihara test?
The published clinical set has 38 plates, though shorter 14- and 24-plate versions are common for screening. This online screen uses a comparable set of original, Ishihara-style plates.
Can the Ishihara test tell protanopia from deuteranopia?
The full clinical set includes classification plates that separate protan from deutan types, but online screens can only estimate this. For a definitive classification, an optometrist may use an anomaloscope or arrangement test.

Keep exploring

What next?

Take the color blind test 14 quick plates · instant type & severity · no sign-up. Start the test → See how you see colour Simulate protan, deutan, tritan & more on any image. Open the simulator → Do colour blind glasses work? Honest comparison of EnChroma, Pilestone & ColorLite. Read the guide →