Is a colour blind test the same as a color blind test?

Yes. "Colour blind test" is the British spelling and "color blind test" the American one; "colour vision test", "color vision deficiency test" and, in much of Europe, "daltonism test" (after John Dalton) all refer to the same screening. Whatever you searched for, this page runs the same test.

Is this color blind test really free?

Yes. The full test — screening, type estimate, and severity — is free with no sign-up, no email, and nothing to buy. It is not a trial for a product; nothing on this page is for sale.

Is an online color blind test accurate?

For screening — telling whether you likely have a color vision deficiency — yes, online tests on a normal screen agree closely with clinical screening. Identifying the exact type and severity is less reliable and should be treated as an estimate.

Can this tell if I am protan or deutan?

It gives an estimate. Distinguishing protan (red-weak) from deutan (green-weak) is genuinely hard without lab equipment, and mild cases are often misclassified between the two, so we label the type as an estimate.

Is this the Ishihara test?

It uses the same pseudo-isochromatic principle as Ishihara/HRR plates, but the plates are generated fresh each time with brightness-noise masking. That prevents memorizing answers and reduces brightness-based guessing.

Do I need to calibrate my screen?

Screening tolerates an uncalibrated screen well. Type and severity are more sensitive to it, which is why we ask you to set full brightness, turn off night-shift filters, and dim the room — and why we report those results as estimates.

Can color blind glasses fix color blindness?

Filter glasses can help some people with red-green weakness distinguish certain colors, but they do not cure color blindness and generally do not help true dichromats or tritan deficiency. Knowing your type is what tells you whether they could help at all.

Color Blind Test

Identify hidden symbols to screen red-green and blue-yellow color vision. Type and severity are estimates, not a diagnosis.

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This free online color blind test screens for color vision deficiency (color blindness) and estimates its type (protan, deutan, or tritan) and severity. It takes about two minutes, needs no sign-up, and stores no personal data. Screening is reliable on a normal screen; the type and severity are best read as estimates, since an uncalibrated display can't fully match a clinical exam.

This test at a glance

Summary of what this free color blind test screens for, what it returns, how long it takes, and its limits
What it screens for	Color vision deficiency (color blindness), including red-green and blue-yellow types
Also searched as	Colour blind test (British spelling), colour vision test, color vision deficiency test, daltonism test — all the same screening
What you get	A screening verdict plus an estimated type (protan, deutan, or tritan) and severity
Time	About 2 minutes (6–10 adaptive plates)
Cost	Free — no sign-up, no email, no purchase
Data stored	None; results stay on your device unless you choose to share
Method	Generated cone-isolation plates with brightness-noise masking and an adaptive staircase
Accuracy	Reliable for screening on a normal screen; type and severity are estimates (uncalibrated display)
Not suitable for	Official requirements — driving, aviation, or occupational medicals need a clinical test

Which color blind test should I take?

Start with a screening — the test above, or the Ishihara test for the classic red-green plates. If it flags a deficiency and you want the type, take an arrangement test such as the Farnsworth D-15; for a graded score of how finely you tell colours apart, the FM-100 Hue. Precise severity for a licence or a job needs a clinical instrument — an anomaloscope or CAD test — which no screen can replace. Whether you searched for a colour blind test, a color vision test or a daltonism test, these are the same six methods.

Ishihara

What it screens: Red-green only
Type information: Protan vs deutan hint
Works on a screen?: Yes — screening is reliable on a normal screen

HRR

What it screens: Red-green and blue-yellow
Type information: Type and rough severity
Works on a screen?: Yes — the closest plate test to full coverage

Farnsworth D-15

What it screens: All three axes, by arrangement
Type information: Plots your confusion axis directly
Works on a screen?: Yes — sorting caps needs no calibration, only ordering

FM-100 Hue

What it screens: Fine hue discrimination, all axes
Type information: Axis plus an error score
Works on a screen?: Partly — ranks you honestly, but absolute scores need calibration

Anomaloscope

What it screens: Red-green, the clinical gold standard
Type information: Precise type and severity
Works on a screen?: No — it needs monochromatic light a screen cannot produce

CAD

What it screens: Red-green and blue-yellow, graded
Type information: Graded severity used for aviation limits
Works on a screen?: No — clinical equipment and calibration required

Which color blind test to take: what each of Ishihara, HRR, Farnsworth D-15, FM-100 Hue, the anomaloscope and the CAD test screens for, what it says about the type, and whether it works on a screen
Test	What it screens	Type information	Works on a screen?
Ishihara	Red-green only	Protan vs deutan hint	Yes — screening is reliable on a normal screen
HRR	Red-green and blue-yellow	Type and rough severity	Yes — the closest plate test to full coverage
Farnsworth D-15	All three axes, by arrangement	Plots your confusion axis directly	Yes — sorting caps needs no calibration, only ordering
FM-100 Hue	Fine hue discrimination, all axes	Axis plus an error score	Partly — ranks you honestly, but absolute scores need calibration
Anomaloscope	Red-green, the clinical gold standard	Precise type and severity	No — it needs monochromatic light a screen cannot produce
CAD	Red-green and blue-yellow, graded	Graded severity used for aviation limits	No — clinical equipment and calibration required

How this test works

1. Screen check

Before you start, set full brightness, turn off blue-light / night-shift filters, and remove tinted lenses. These reminders matter because an uncalibrated screen is the biggest source of error.

2. Cone-isolation plates

You read hidden numbers or shapes in generated pseudo-isochromatic plates that isolate each cone (red, green, blue) in turn. An adaptive staircase lowers the color contrast toward your threshold, and per-dot brightness noise means only color — not lightness — gives the answer away. Fresh plates each time, so you can't memorize them.

3. Cone scores → type & severity

Your three cone scores (0–100) show where a deficiency is and how strong it is — red-weak (protan), green-weak (deutan), or blue-yellow (tritan). Since your screen isn't calibrated, treat the type and severity as estimates for self-tracking rather than a clinical measurement.

What your result tells you

Do you have a deficiency? This is the part to trust. On any normal screen, the yes-or-no screening holds up about as well as a clinic's first-pass test.
Which type is it? Read this as a strong hint, not a label — red-weak (protan), green-weak (deutan), or blue-yellow (tritan). Mild red and green are the easiest to mix up.
How strong is it? You get a relative score, handy for comparing one attempt with the next. It isn't a calibrated clinical grade.
Need it for something official? For a driving licence, a job, or a medical question, have it confirmed by an eye-care professional (an anomaloscope or CAD test).

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.

Frequently asked questions

Is a colour blind test the same as a color blind test?: Yes. "Colour blind test" is the British spelling and "color blind test" the American one; "colour vision test", "color vision deficiency test" and, in much of Europe, "daltonism test" (after John Dalton) all refer to the same screening. Whatever you searched for, this page runs the same test.
Is this color blind test really free?: Yes. The full test — screening, type estimate, and severity — is free with no sign-up, no email, and nothing to buy. It is not a trial for a product; nothing on this page is for sale.
Is an online color blind test accurate?: For screening — telling whether you likely have a color vision deficiency — yes, online tests on a normal screen agree closely with clinical screening. Identifying the exact type and severity is less reliable and should be treated as an estimate.
Can this tell if I am protan or deutan?: It gives an estimate. Distinguishing protan (red-weak) from deutan (green-weak) is genuinely hard without lab equipment, and mild cases are often misclassified between the two, so we label the type as an estimate.
Is this the Ishihara test?: It uses the same pseudo-isochromatic principle as Ishihara/HRR plates, but the plates are generated fresh each time with brightness-noise masking. That prevents memorizing answers and reduces brightness-based guessing.
Do I need to calibrate my screen?: Screening tolerates an uncalibrated screen well. Type and severity are more sensitive to it, which is why we ask you to set full brightness, turn off night-shift filters, and dim the room — and why we report those results as estimates.
Can color blind glasses fix color blindness?: Filter glasses can help some people with red-green weakness distinguish certain colors, but they do not cure color blindness and generally do not help true dichromats or tritan deficiency. Knowing your type is what tells you whether they could help at all.

Understand your result

Red-green color blindness

The most common family: what gets confused and why.

Protan vs deutan

The two red-green types side by side, and how to tell which is yours.

What do color blind people see?

Simulations and honest descriptions, type by type.

Do color blind glasses work?

What filter lenses can and cannot do for each type.

Hard color blind test

The same adaptive plates with no warm-up, a 3-second limit and no second look.

Color blindness simulator

See any image with protan, deutan or tritan vision at any severity.