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Stroop Test Online: How It Works and What Your Score Means
By HumanCalc · Published · 3 min read
The Stroop test shows a color word printed in a color. Your job is to name the ink and ignore the word. When the word BLUE is printed in red ink, the right answer is red, and most people answer it more slowly than they would if the word and the ink agreed.
That slowdown is the Stroop effect. John Ridley Stroop described it in 1935, and it has been studied in hundreds of experiments since. HumanCalc's version runs for 45 seconds and counts how many ink colors you name correctly.
A worked example
Four trials
- GREEN printed in green ink: answer green. Word and ink agree, so this one is quick.
- BLUE printed in red ink: answer red. The word pulls you toward blue.
- YELLOW printed in blue ink: answer blue.
- RED printed in yellow ink: answer yellow.
Answer with the ink every time. The word is there to distract you.
Why the word gets in the way
For a fluent reader, reading a short word happens without effort and without being asked. Naming a color is slower. In the mismatched trials, both answers arrive at once and the reading answer arrives first, so you have to hold it back before you can say the ink color.
In Stroop's own experiments, people took longer to name the ink colors of mismatched color words than to name the colors of plain colored patches. MacLeod's 1991 review covers the first half-century of research that followed.
How HumanCalc's version is scored
- A run lasts 45 seconds. Your score is the number of correct answers in that time.
- Each word has its own answer window. It starts at 3.0 seconds and shrinks by 0.25 seconds after five correct answers in a row, down to 1.25 seconds. Two misses in a row widen it again.
- A wrong answer or a missed window does not end the run. It costs you the time and the point.
- Answer with the four buttons or the keys 1 to 4. The order of the buttons stays fixed during a run.
What 34 players scored
These figures come from HumanCalc players between 14 and 26 October 2026. A score in the high 30s is typical here. Above 40 is a strong run on this version of the test.
| Measure | Correct answers in 45 s |
|---|---|
| Median run (52 runs) | 35 |
| Middle half of personal bests | 26–37 |
| Top 10% of personal bests | 40 or more |
| Highest personal best | 51 |
How to raise your score
A browser score is a practice result. Clinical Stroop tests use printed cards or fixed software, set timing and published norms.
- Look at the middle of the word, slightly unfocused. The color is easier to pick up than the letters.
- Use the number keys if you are on a computer. Moving a mouse between buttons costs time on every trial.
- Learn the button positions before the run starts so you do not have to search for them.
- Slow down after a mistake. A second error in a row usually comes from rushing the next word.
- Compare runs played at the same time of day. Tiredness shows up quickly in this task.
Research sources
Try it now
Play Stroop Test in your browser
Name the ink color, ignore the word. About 2 min. Free, no signup.
Play Stroop Test