Read the number hidden among the coloured dots. Twelve plates screen red-green and blue-yellow color vision
How the plates work
The method comes from Shinobu Ishihara at the University of Tokyo in 1917. The digit and the background are dotted in colours of similar brightness but different hue. With no brightness cue, only hue separates them โ and if you have a red-green deficiency, red, orange and yellow-green collapse into one and the digit sinks into the background. The plates here are generated fresh each time, so they cannot be memorised.
How common it is
Red-green deficiency affects roughly 8% of men and 0.5% of women โ it is carried on the X chromosome. That is one in twelve men, and most go through school without knowing, because mild cases do not interfere with traffic lights or daily life. Blue-yellow deficiency is far rarer (under 1 in 10,000), so if you missed the blue-yellow plates, suspect your screen settings before your eyes.
| Red-green (protan / deutan) | 8% of men, 0.5% of women. Red, green and brown blur together |
|---|---|
| Blue-yellow (tritan) | Under 1 in 10,000. Blue, yellow and purple blur |
| Total color blindness | About 1 in 30,000. Very rare |
Your screen changes the result
This is a screen, not a printed booklet. Night mode, blue-light filters and low-saturation settings will make people with normal vision miss plates. Turn brightness up and switch every colour filter off before you start. If plates you missed become readable after changing settings, it was the display.
If the result worries you
This is a screening, not a diagnosis. A proper assessment uses printed Ishihara plates plus an arrangement test (FM-100) or an anomaloscope to identify the type and severity. Driving licences and some occupations (aviation, rail, police) have defined standards, so if that applies to you, get the clinical result.
How to take it
- Turn brightness up, switch off night mode and any blue-light filter, then press START.
- A round plate of dots appears with a "1 / 12" counter above it. Read the two-digit number in the dots.
- Pick it from the five choices below. The wrong choices differ from the answer by one digit, so a half-read plate is easy to get wrong. If you cannot make out a number, tap Nothing โ a lucky guess skews the result.
- The next plate loads immediately. After twelve you get a verdict and a "N of 12 plates read" count.
- Share the result as a link, or tap Again for a fresh set of plates.
Plate mix and how the verdict is decided
Of the twelve plates, eight test red-green and four test blue-yellow, in a fixed order with a blue-yellow plate in every third position. Red-green plates use yellow-green digits on an orange and apricot background; blue-yellow plates use pale blue digits on grey-brown. The number is drawn at random from 10 to 99, around 1,400 non-overlapping dots of varying size fill the disc, and only the dots that land on the digit shape take the second palette โ so there is no outline to follow.
Red-green and blue-yellow are scored separately.
| No sign of deficiency | At least 7 of the 8 red-green plates and 3 of the 4 blue-yellow plates |
|---|---|
| Possible red-green deficiency | 3 or fewer of the 8 red-green plates |
| Possible blue-yellow deficiency | 4 or more red-green plates, but 1 or fewer blue-yellow plates |
| Borderline | Anything else โ 4 to 6 red-green plates, or 7 or more with exactly 2 blue-yellow |
There is no leaderboard for this test. Colour vision is not a score to compete on, and the result only means something if you tap Nothing honestly, so sharing is the only option.
Frequently asked questions
Do the same plates come back?
No. The digits, dot layout and dot colours are regenerated every time you start, so a retry is a completely different set. Expect one or two plates of variation between runs; the verdict you get two or three times in a row is the one to trust.
I have a known deficiency but read every plate
The test uses just two colour pairings โ one for red-green, one for blue-yellow โ rather than the many combinations a clinical booklet uses to separate types and severities. A mild deficiency can get through this pairing, particularly on a bright, saturated display. Equally, someone with normal vision missing a few plates is almost always a display issue. Either way it does not replace a clinical test.
Can children take it?
Yes, if they can read two-digit numbers โ answers are picked from buttons, nothing is typed. Clinical tests for young children use shapes and paths to trace instead of digits, so if a child misses several plates here, that is the version an optometrist would use to check.
Why are there fewer blue-yellow plates?
Blue-yellow deficiency is far rarer, and blue-yellow plates are the ones most affected by a screen's colour temperature, so even normal vision drops them. Four plates are enough, and the threshold for flagging blue-yellow is deliberately lenient โ one plate or fewer.
What goes into the shared link?
Only the number of plates read and which verdict you got. Nothing is stored on a server, and there is no account.
Related tools
- Color Spot Test โ you can tell colours apart, but how fine a difference can you catch?
- Color Mixing Test โ producing a colour rather than recognising one
- Personal Color Analysis โ which palette suits your skin and hair
- Dynamic Vision Test โ the eye's other job: reading things in motion