Stroop Testtake the Stroop effect test online, free
Name the colour of the ink, not the word. A timed colour-word run that measures your reaction time, accuracy, and Stroop interference — no download, no sign-up, right in your browser.
Time
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Score
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Acc
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Streak
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Ready?
Answer the ink colour, not the word.
Name the ink colour, not the word — as fast as you can before the timer runs out
What is the Stroop test
Name the colour. Ignore the word. Fight your own reflex.
The Stroop test is a classic cognitive-psychology task, first described by John Ridley Stroop in 1935. A colour word flashes on screen in a mismatched ink, and you answer the ink colour as fast as you can. Reading is automatic, so the word fights you — and the time that fight costs is the Stroop effect. This version turns it into a quick, scored run with instant results.
- 30s, 60s, or 2 min
- Pick a sprint, the standard minute, or a two-minute deep run. Same six colours every time, so scores compare cleanly across lengths.
- Runs in your browser
- No download, no install, no sign-up. strooptest.app loads the start screen instantly on desktop and mobile.
- Real reaction-time metrics
- Every run reports mean reaction time, accuracy, longest streak, and Stroop interference — the milliseconds the mismatched word costs you.
- History saved locally
- Best score, best accuracy, fastest reaction time, and your last twelve runs are stored on your device — never on a server.
How it works
Four steps, then the numbers
The Stroop test is one instruction — answer the ink, not the word — repeated as fast as you can for a timed run. Here is the whole loop.
- 1
Pick a run length
Choose a 30-second sprint, the 60-second standard run, or a two-minute deep test on the start screen. Every run uses the same six colours — red, blue, green, yellow, purple, and orange — so your scores are comparable across lengths.
- 2
Read the ink, not the word
A colour word appears in the centre of the card, printed in one of the six inks. Your job is to answer the colour of the ink and ignore what the word actually says. When the word "GREEN" is printed in red, the answer is red.
- 3
Answer as fast as you can
Tap the matching colour button, or press its number key 1–6 on a keyboard. The moment you answer, the next word appears. A correct answer adds points scaled by how quickly you responded; a wrong answer scores nothing and resets your streak.
- 4
Read your results
When the clock hits zero you get your score, accuracy, mean reaction time, longest streak, and Stroop interference — the extra milliseconds the incongruent words cost you compared with the matching ones. Every run is saved to this device so you can watch the trend.
Tips for a better score
- Fix your eyes on the centre of the card before the countdown ends so the first word does not surprise you.
- Rest your fingers on the 1–6 keys (or hover your thumb over the buttons) so answering is one motion, not two.
- Name the colour silently — "red", "blue" — instead of trying to not-read the word. Suppression is slower than substitution.
- Keep a steady rhythm. Rushing one answer usually costs you the next two in mistakes.
- If you slip, let it go instantly. Dwelling on a wrong answer is what turns one error into a broken streak.
- Take the same run length each time. Reaction time and interference only mean something when you compare like with like.
- Check your interference score, not just accuracy. Two people can both score 95% and have very different Stroop costs.
FAQ
The Stroop test, answered
Straight answers about the free Stroop effect test you can take online in your browser.
What is the Stroop effect?
The Stroop effect is the delay and extra errors that happen when you try to name the ink colour of a word whose meaning is a different colour — for example the word "RED" printed in blue. Reading is so automatic for fluent readers that the brain processes the word even when the task is to ignore it, and overriding that takes measurable extra time. It was first described in detail by John Ridley Stroop in 1935.
What is the Stroop test?
The Stroop test is the task built around the Stroop effect. You are shown colour words printed in various inks and must respond with the ink colour, not the word. This browser version flashes one word at a time for a timed run and records how fast and how accurately you answer, plus your Stroop interference score.
Is the Stroop test free to take online?
Yes. strooptest.app is completely free and runs entirely in your browser. There is nothing to buy, download, or install, and there is no sign-up. Open the page and the start screen is ready.
How do I take the test?
Pick a run length (30 seconds, 60 seconds, or two minutes), wait out the 3·2·1 countdown, then answer each word by tapping the colour button that matches the ink or pressing its number key 1–6. Keep going until the timer reaches zero, then read your results.
What is the difference between congruent and incongruent trials?
A congruent trial is one where the word and its ink match — "GREEN" in green ink — so reading and colour naming agree and you answer quickly. An incongruent trial is one where they disagree — "GREEN" in orange ink — so you have to suppress the word to name the ink, which is slower. About 70% of trials in a run are incongruent.
What is the interference score?
Interference is your mean reaction time on incongruent trials minus your mean reaction time on congruent trials, in milliseconds, counting only correct answers. It isolates the cost of the conflicting word from your general speed. A lower interference number means you are better at filtering out the distracting word. Typical values fall somewhere between about 50 ms and 250 ms.
How does scoring work?
Each correct answer is worth a base of 20 points plus a speed bonus of up to about 120 that shrinks as your reaction time grows, all multiplied by a streak bonus that increases 25% for every five correct answers in a row. Wrong answers and trials you did not answer before time ran out score zero and reset the streak.
What is a good Stroop test score?
On the 60-second run, most people land around 85–95% accuracy with a mean reaction time between 700 ms and 1100 ms and interference of 80–200 ms. Faster reaction times, accuracy near 100%, and a smaller interference number are all better, but the useful comparison is against your own past runs on the same length.
Does the test save my results?
Your best score, best accuracy, fastest mean reaction time, longest streak, lowest interference, and your last twelve runs are saved locally in your browser. Nothing is sent to a server and there is no account. A run in progress is not saved if you close the tab, and clearing site data erases the history.
Can I take the Stroop test on my phone?
Yes. The word card and all six colour buttons fit on one portrait screen with no scrolling, and buttons are sized for a thumb. Starting a new run is instant with no page reload.