A colour perception test measures your colour discrimination — how small a difference in shade your eye can actually detect. Here, a grid of squares is all one colour except a single square that's slightly off, and you have to spot it. Every level the grid grows and the difference shrinks, so the point where the odd square finally hides from you is the edge of your colour sensitivity. Here's what your score means and how to push it.
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Finding one slightly different square among many is a classic side-by-side discrimination task — and the eye is unusually good at it, far better than judging a colour in isolation. As the grid enlarges and the shade gap narrows, you're being pushed toward your just-noticeable difference: the smallest change in colour you can reliably perceive. Reaching a high level means your eye is resolving very fine differences under real-world screen conditions.
A good score is simply reaching a high level — a large grid with a tiny difference. But there's an honest caveat: your screen and lighting matter as much as your eyes. Brightness, contrast, colour calibration, glare and even the angle you view the panel from all change what's visible. Because of that, there's no universal target number; the fair benchmark is your own best on the same screen in the same lighting. For anyone with normal colour vision, reaching the levels where the difference is barely perceptible is a strong result.
People with normal colour vision can distinguish on the order of a million colours, thanks to three types of cone cell in the retina, each tuned to a different band of wavelengths. Sensitivity varies naturally between people, and it always drops when a colour is dim, small, or surrounded by very similar shades — which is exactly the challenge this test ramps up level by level.
🎨 Take the colour perception test →
A colour-discrimination task: find the one square that's a slightly different shade. The grid grows and the difference shrinks each level, marking the limit of your colour sensitivity.
Reaching a high level with a large grid and tiny difference. Screen and lighting matter as much as your eyes, so compare against your own best on the same screen.
People with normal colour vision distinguish roughly a million colours via three cone types. Sensitivity drops when colours are dim, small or surrounded by similar shades.
No — it's a general game, not a clinical screen. See an optometrist for a proper colour-vision assessment.