How to take the test
You see four rows of colored chips. The first and last chip in each row are fixed and marked with a dot. The chips in between are shuffled. Your job is to put them in order so the color changes in small, even steps from one end of the row to the other.
- Click a chip to pick it up, then click the spot where it belongs. The chip moves there and the others shift along.
- With a chip selected, the left and right arrow keys move it one place at a time. Esc puts it down.
- Click a fixed end chip while holding another chip to move it next to that end.
When you are happy, press Score my arrangement. You can shuffle and try again at any time.
Where the idea comes from
The Farnsworth-Munsell 100 Hue test was developed by Dean Farnsworth in the 1940s. It uses 85 colored caps of equal lightness and saturation, split across four trays, which the patient arranges by hue under a standard daylight lamp. It measures how finely someone discriminates hue and can show the pattern of a color vision deficiency.
This version borrows the format, not the materials. It has 44 chips around the hue circle, all with the same OKLCH lightness (0.70) and chroma (0.085), so only hue changes along each row. Neighbors differ by about 8 degrees of hue, which is enough to be challenging on a good screen without being impossible.
How the score is calculated
The scoring follows Farnsworth's method. Each chip has a number for its correct place. For every movable chip, the tool adds the difference to its left neighbor and its right neighbor, then subtracts 2:
error = |this − left| + |this − right| − 2
A chip in the right place, between its true neighbors, scores 0. Swapping two adjacent chips gives a small error; dropping a chip far from home gives a big one. The total error score adds up every chip, and each row also gets its own subtotal.
| Total error score | What it suggests |
|---|---|
| 0 | A perfect arrangement |
| 1–16 | A few small slips, common on screens and when tired |
| 17–60 | Some chips clearly out of place |
| Over 60 | Many chips out of place; retest in better conditions |
These bands are HexaCalc's own guide for this 44-chip screen version. They are not clinical norms, and the scores cannot be compared with official FM100 results.
Reading the polar plot
The circle shows every chip at its hue angle. Where you made errors, the outline bulges outward. Errors spread evenly suggest general difficulty, or a screen that makes the test hard. Errors bunched on two opposite sides of the circle form an axis, which is the pattern Farnsworth used to tell types apart: red-green deficiencies and tritan deficiencies produce axes in different directions.
On a screen test, take any axis with caution. A single bad row can create one by chance. Retake the test before reading anything into it.
Getting a fair result
- Use a bright, color-accurate screen with night modes switched off.
- Sit in even, neutral room light, not under colored bulbs.
- Take your time. The original test has no strict time limit, and rushing inflates the score.
- Try two or three times. Scores usually improve as you learn what to look for.
What affects hue discrimination
Hue discrimination varies more than most people expect. It tends to decline gradually with age, as the lens yellows and blue-green differences become harder to see. Fatigue, some medications and eye conditions also affect it, and so do inherited color vision deficiencies. Practice helps too: designers, printers and painters often score better because they compare subtle colors every day.
This is not a medical test. If you notice a change in how you see colors, see an eye care professional.
Related tools
For a quick screen for red-green and blue-yellow deficiencies, take the color blind test. The color blindness simulator shows how palettes look with each type, and the color game trains your eye with daily rounds. To explore how hues relate around the circle, open the color wheel.
FAQ
Why are the colors so similar?
That is the point. The test measures fine discrimination. With big steps between chips, everyone would score 0.
Is a high score a sign of color blindness?
Not on its own. Screens, lighting and attention have big effects here. A consistently high score, especially with a clear axis, is a good reason to have your color vision tested properly.