Color Perception Test
One tile in the grid is a slightly different shade. Click it to move to the next level. Each level the grid grows and the two colors get closer, measured in ΔE (the standard color-difference unit). How fine can your eyes go?
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Tip: set screen brightness high and turn off night-light / blue-light filters. Keyboard: arrow keys + Enter.
How to use the Color Perception Test
- Choose a mode: Classic (3 lives) or Timed (60 seconds).
- Press Start test and look for the tile whose color is slightly different.
- Click the odd tile. A correct click moves you to a harder level right away.
- Wrong click? In Classic you lose a life and the odd tile is shown; in Timed you lose 3 seconds.
- Read your result: your level, the smallest color difference you found and your history.
How the difficulty increases
Every level picks a new random base color in the CIELAB color space and shifts one tile by a target distance: in lightness, in saturation (chroma), in hue, or in a mix of all three. The target starts at ΔE 25 and shrinks by 12% per level, so level n uses ΔE ≈ 25 × 0.88n−1. The ΔE shown on screen is measured after the colors are rounded to the 8-bit values your screen actually displays.
| Level | Grid | Color difference | What it looks like |
|---|---|---|---|
| 1 | 2 × 2 | ΔE ≈ 25 | Obvious at a glance |
| 5 | 5 × 5 | ΔE ≈ 15 | Clearly different |
| 10 | 6 × 6 | ΔE ≈ 7.9 | Easy to spot when you scan |
| 15 | 7 × 7 | ΔE ≈ 4.2 | Subtle |
| 20 | 8 × 8 | ΔE ≈ 2.2 | Near the just noticeable difference |
| 25 | 8 × 8 | ΔE ≈ 1.2 | Very hard; depends on screen and light |
| 28+ | 8 × 8 | ΔE ≈ 0.6 to 0.8 | At the limit of 8-bit color steps |
The ΔE formula
CIELAB describes a color with three numbers: L* (lightness, 0 to 100), a* (green to red) and b* (blue to yellow). The CIE76 color difference between two colors is the straight-line distance between them:
ΔE*ab = √((L*₂ − L*₁)² + (a*₂ − a*₁)² + (b*₂ − b*₁)²)
A value of about 2.3 is widely cited as a just noticeable difference for CIE76. Later formulas such as CIEDE2000 correct for the fact that the eye is more sensitive to some color directions than others, which is why some ΔE 3 levels in this test feel harder than others.
Getting a fair result
- Turn off night-light, blue-light filters and "reading mode": they compress colors and hide differences.
- Use high brightness and look at the screen straight on. Many laptop and TN panels shift color with viewing angle.
- Avoid glare and strongly colored room light.
- Scan in rows instead of staring at the center: small differences often pop out at the edge of your attention.
- Compare like with like. Scores on different devices are not directly comparable.
Frequently asked questions
How does the color perception test work?
Each level shows a grid of identical tiles with one tile in a slightly different color. Level 1 uses a 2×2 grid and a large difference (ΔE about 25). With every level the difference shrinks by 12% and the grid grows, up to 8×8. Your score is the number of levels you cleared.
What does ΔE mean?
ΔE (delta E) measures the distance between two colors in the CIELAB color space, which was designed so that equal distances look roughly equally different. This test uses the simple CIE76 formula: ΔE = √(ΔL*² + Δa*² + Δb*²). A ΔE of about 2.3 is often quoted as a just noticeable difference; below 1 most people cannot tell two colors apart side by side.
What is a good score?
There is no official standard for this game. Reaching levels where the difference is around ΔE 3 to 2 (roughly level 18 to 21) means you can see very small shade changes. Levels beyond that depend heavily on your screen, its brightness and the room light.
Does my screen affect the result?
Yes, a lot. Screen calibration, brightness, viewing angle, night-light or blue-light filters, color profiles and low-quality panels can hide or exaggerate small differences. For a fair comparison, use the same device and lighting each time and look at the screen straight on.
Is this a color blindness test?
No. It measures how small a shade difference you can find on your screen, not which colors you confuse. Color vision deficiency is diagnosed by an eye care professional; our Color Blindness Test and Color Hue Test are other screen-based self-checks, but neither replaces an exam.
Is my score history private?
Yes. Your last 30 results are kept only in this browser's local storage. Nothing is sent anywhere.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.