Red-green colour blind test

Please read the number in each dot plate. There are 9 plates: 1 practice plate and 8 red-green plates. Red-green deficiency is the most common type; the US National Eye Institute states that about 1 in 12 men have a colour vision deficiency. This test cannot replace an eye test.

0 of 9 plates answered

Before you start, please:

  • Turn up the screen brightness and turn off night mode, eye comfort mode and blue light filters.
  • Sit about an arm's length from the screen in normal indoor light.
  • Wear your glasses if you usually wear them.

Result

Your result will appear here after you answer all 9 plates.

This is a self-check on a screen. It cannot replace a colour vision test by an eye doctor, and the colour, brightness and eye comfort settings of your screen affect the result. For a medical, job or driving licence requirement, the test by the concerned authority or hospital shall prevail.

Your results are calculated and saved only in this browser. They are not uploaded to our server. Select “Reset” to clear them.

Method and sources of error

  1. Each plate is made of about a thousand dots of different sizes. The colours of the number and of the background differ only in a direction that people with one type of colour vision deficiency cannot distinguish: red-green (red) plates change only the stimulus to the L cones, red-green (green) plates only the M cones, and blue-yellow plates only the S cones. The cone stimulus is calculated with the conversion given by Viénot, Brettel and Mollon (1999).
  2. The brightness of each dot varies at random by about ±12%, in the same way for the number and the background, so the number cannot be read from light and dark alone.
  3. Each type of plate has been checked with the colour vision simulation model of Machado and others (2009): under the matching simulated deficiency, the number and the background are almost the same colour; with normal colour vision they differ clearly.
  4. The number on the practice plate is clearly darker than the background, so anyone should be able to read it. It confirms that the screen displays correctly and that your answers are recorded. New plates and numbers are generated for each test.
  5. Scoring rule (original to this website and not clinically validated): no conclusion is given if the practice plate is read incorrectly; 2 or more incorrect red-green plates, or 1 or more incorrect blue-yellow plates, lead to “you may have a difference”. The test cannot distinguish colour blindness from colour weakness, and cannot judge the degree of a deficiency.
  6. Sources of error: screen colour calibration, brightness, night mode, blue light filters, the colour range of the display and the viewing angle all change the colours. Phones that adjust colours to the room light also affect the result.

About colour vision deficiency

  • The US National Eye Institute states that colour vision deficiency (colour blindness) means seeing colours differently from most people. The most common type makes it hard to tell red from green; another type makes it hard to tell blue from yellow. Seeing no colour at all is rare.
  • Men have a much higher risk than women: about 1 in 12 men have a colour vision deficiency.
  • Eye doctors usually check colour vision with plates made of coloured dots.

Sources

  1. National Eye Institute: Color Blindness
  2. Machado, Oliveira, Fernandes (IEEE TVCG, 2009): A Physiologically-based Model for Simulation of Color Vision Deficiency
  3. Viénot, Brettel, Mollon (Color Research & Application, 1999): Digital video colourmaps for checking the legibility of displays by dichromats

Last checked: 31 October 2026.