Color Blindness Test

How to Take the Color Blindness Test

1. Sit a comfortable arm's length from your screen and set the brightness to a normal, neutral level. Avoid coloured lighting or a screen night-shift mode, which both distort the plates.
2. Look at each Ishihara-style plate and type the number you can read into the box. If you can't make out a figure, leave it blank and move on — don't strain or guess.
3. Work through every plate at a steady pace. The hidden numbers use colours that contrast for typical vision but blend together for specific colour deficiencies.
4. After the final plate you'll see how many you matched and what that may suggest about your colour vision.
5. If the result surprises you, re-run it once in good, neutral lighting before reading anything into it — screen and lighting conditions matter.

What Your Results Mean

You read most or all plates correctly: your colour vision is likely typical for the red-green range these plates screen. This is the most common outcome.

You miss several red-green plates: this can indicate a red-green colour vision difference (protan or deutan), the most common type. It's an indication only — not a diagnosis.

You see a different number than expected on certain plates: some plates are designed so that people with a colour deficiency read a different figure. Seeing the alternate number is itself a screening signal worth following up.

Your result differs between devices: that's expected. Uncalibrated screens, brightness, and room lighting all shift how the colours appear, which is exactly why an online test can indicate but never diagnose.

Types of Color Blindness

Red-green deficiency is by far the most common and comes in two main forms: protan types, where red perception is reduced or absent, and deutan types, which affect green. It affects roughly 1 in 12 men and about 1 in 200 women, because the genes involved sit on the X chromosome. Blue-yellow deficiency (tritan) is much rarer and affects men and women about equally, and total colour blindness, where little or no colour is seen at all, is very rare. Our guide on the types of colour blindness explains each in more detail.

How Accurate Is an Online Test?

Treat this as a quick screening, not a clinical result. Ishihara-style plates are a well-established first-line check, but on a computer their accuracy depends on your display. Monitor calibration, brightness, blue-light filters and ambient lighting all change how the dots look, so a clear result still warrants a proper exam. An optometrist uses printed, calibrated plates under controlled lighting, plus additional tests, to confirm the exact type and severity. If you have everyday trouble distinguishing colours — at traffic lights, on charts, or matching clothes — book an eye exam regardless of what an online screen shows.

Can Color Blindness Be Corrected?

There's no cure, but it's usually mild and manageable. Most people with a red-green deficiency still distinguish many colours and adapt without difficulty. Some find specialised lenses help them tell certain colours apart, and the accessibility settings on phones and computers can label or adjust colours to make screens easier to read.

What Causes Color Blindness

The vast majority of colour vision deficiency is inherited. The genes for red and green cone sensitivity sit on the X chromosome, which is why red-green deficiency is so much more common in men — they have only one X, so a single affected gene shows, while women usually have a second X to compensate. That's the reason roughly one in twelve men and only about one in two hundred women are affected. A smaller share of cases is acquired later in life, caused by ageing, eye conditions such as cataracts or glaucoma, diabetes, certain medications, or injury to the eye or the optic nerve. Acquired deficiency can affect one eye more than the other and can change over time, whereas inherited deficiency is stable and present from birth in both eyes equally — a useful clue when something seems to have changed.

Living and Working With Color Vision Deficiency

For most people it's a mild, manageable difference rather than a disability, and a few habits and tools smooth over the friction. Modern phones and computers include accessibility colour filters — on Windows 11, Settings → Accessibility → Colour filters, and on macOS, System Settings → Accessibility → Display → Colour filters — that can shift problem hues into more distinguishable ranges. When colour carries important meaning, such as in charts, transit maps or status lights, looking for labels, patterns, position or brightness instead of relying on hue alone removes most of the difficulty; well-designed software increasingly does this for you. Some people also find specialised glasses help them separate certain reds and greens, though results vary by individual and by the exact type of deficiency. It's worth knowing that a few careers with strict colour-recognition requirements — some aviation, military and electrical roles — do test for it, so an early, proper diagnosis is genuinely useful to have.

How Ishihara Plates Reveal Color Blindness

The dotted circles in this test are based on Ishihara plates, a method in use since 1917. Each plate hides a number or path in dots that differ from the background mainly in hue rather than brightness. To someone with typical colour vision the figure stands out clearly; to someone with a red-green deficiency the relevant dots blend into the background and the number becomes hard or impossible to read. Some plates are designed so that a person with a deficiency reads a different number than someone without — which is why seeing the "wrong" figure on certain plates is itself a screening signal. Because the method leans on subtle hue differences, screen calibration, brightness and room lighting all sway the outcome, and that's exactly why an online version screens rather than diagnoses.

Frequently Asked Questions

Related: How to test for colour blindness online →  ·  Types of colour blindness →