Color Vision Test

What is a colour vision test?

Every round shows a grid of tiles in a single colour, except one that is a very slightly different shade. You tap the odd one out. Each level the grid grows and the difference shrinks, until you are staring at squares that look genuinely identical and guessing.

What this measures is colour discrimination, meaning how small a difference in hue or lightness your eyes and brain can separate. That is a different thing from colour blindness. A colour blind person confuses particular colour pairs regardless of how far apart they are, and this test is not designed to detect that. Plenty of people with entirely typical colour vision still stall around level twelve, because discrimination varies enormously between individuals.

How to play

1. Find the tile that is a slightly different shade.
2. Tap it to advance. The grid grows and the difference gets subtler.
3. Get it wrong and the run ends. Your best level is saved.

Why it gets impossible so fast

Two things are working against you at once. The grid grows, so there is more to scan, and the colour gap narrows, so each comparison is harder. Human vision is also much better at judging two colours that touch than two separated by other tiles, which is why the odd tile is far easier to find when it happens to sit next to the tile you are looking at.

Your screen is a real limit here too. An older or cheaper panel simply cannot display the difference between two shades a few values apart, so beyond a certain level you are testing your monitor rather than your eyes. Brightness matters as well: at low screen brightness the darkest steps compress together and become genuinely indistinguishable.

How to get further

• Turn your brightness up. The single biggest factor, and most people play with it far too low.
• Scan in rows, not randomly. Comparing each tile against its neighbour is far more sensitive than hunting for something that looks wrong.
• Defocus slightly. Letting your eyes go soft makes an odd tile pop out of the field, because peripheral vision is better at detecting difference than at identifying detail.
• Tilt your phone. Most phone screens shift colour with viewing angle, which can exaggerate a difference you cannot otherwise see.
• Do not stare. Fixing on one spot causes local adaptation, and after a few seconds your eyes literally stop registering the difference.

What a good score looks like

Most people stop somewhere between level ten and fifteen. Past twenty is genuinely strong, and anything higher usually means both good discrimination and a good screen. Women are somewhat more likely to reach the higher levels, since red-green colour deficiency is far more common in men, affecting roughly one in twelve compared with about one in two hundred.

If you suspect an actual colour vision deficiency, this is not the right tool. Ishihara plates and proper clinical testing exist for that, and an optician can do it properly in a few minutes. Your best level here is saved in your browser and no account is needed.