Instant to start
Open the page and the start screen is already there. No account wall, no download, no explainer video — pick a length and the countdown begins.
About Us
About strooptest.app
We publish a free, modern browser version of the Stroop effect test — the 1935 colour-word interference task — with 30-second, 60-second, and two-minute runs, keyboard and touch controls, and a real interference score.
Our craft
One reflex, measured cleanly.
Name the ink, ignore the word, and let the milliseconds show what your attention is doing. That loop is everything we design around.
- Ink colours
- 6
- Run lengths
- 3
- Year first measured
- 1935
Ink colours
Run lengths
Year first measured
What we make
A free Stroop test that stays in the browser
strooptest.app is the site behind our version of the Stroop colour-word task. It is a single-player test: a colour word flashes in a mismatched ink and you respond with the ink colour, over a timed run, while it records your speed and accuracy.
We are not an app-store publisher and there is nothing to download. The test is the website. That keeps load times short, works on phones and desktops alike, and avoids an account wall. Best scores, reaction times, and your last twelve runs live in local browser storage on your device.
If you are comparing this to another Stroop site, this page only speaks for strooptest.app. The mechanics, scoring, and interference metric described in our how-it-works guide and FAQ match this exact build.
Our story
From a 1935 thesis to your browser tab
The Stroop task is one of the longest-running measures in psychology still in daily use. We treat that as a responsibility to get the method right and the friction as close to zero as we can.
- 01
The 1935 experiment
John Ridley Stroop, working on his doctorate at George Peabody College, published "Studies of interference in serial verbal reactions." He showed that naming the ink colour of mismatched colour words took dramatically longer than reading the words or naming colours of plain shapes. The task has carried his name ever since.
- 02
A lab staple
Because it is quick, repeatable, and needs only cards or a screen, the Stroop task became one of the most-used measures in cognitive psychology and neuroscience — a standard probe of attention, processing speed, and the ability to suppress an automatic response.
- 03
This build
strooptest.app is an independent, modern implementation of the colour-word task. The core is unchanged; what is new is a rendering that is smooth on a phone, millisecond timing, a live score, a real interference metric on the results screen, and a local history so you can watch your own trend.
What we stand for
Principles behind every run
Honest measurement
Real reaction times in milliseconds, a proper congruent-versus-incongruent interference figure, and a run history you can actually compare. No vanity numbers.
Yours to keep
Best score, best accuracy, fastest reaction time, and your last twelve runs live on your device. There is no login because there is nothing to log in to.
Free, for real
The whole test is free forever. No timed paywall on the two-minute run, no interstitial ads between attempts, no "unlock your full results" upsell.
Who it is for
Anyone curious how their attention handles conflict
strooptest.app is a family-friendly, single-player test with no chat and no store. A poor fit if you want a clinical assessment; a good fit if you want the real Stroop task, measured properly, on whatever screen is nearby.
Short sessions
A run is 30 seconds to two minutes. The Stroop test is built for a phone on the couch or a browser tab between tasks, not a long sitting.
Curiosity, not diagnosis
It is a window into how your attention handles conflict. It is not a medical test and cannot diagnose anything — the numbers move with sleep, caffeine, and screen.
Play without an account
Your history stays on the device you used. That is a deliberate trade: instant start and real privacy, with no cloud restore.
Why this site
How strooptest.app is different
There are many Stroop pages online. This one exists to ship a single honest, fast version — real timing, a proper interference score, and no clutter.
A real interference score
Most online versions give you a raw time. This one separates the Stroop cost from your general speed by reporting incongruent minus congruent reaction time — the number the original experiment was about.
Keyboard-first timing
Number keys 1–6 map to the six colours so a correct answer is one keypress. That keeps recorded reaction times honest instead of dominated by mouse travel.
No clutter
No auto-playing video, no fake "install our app" banner, no dark patterns around the results. The how-it-works guide and FAQ describe this exact build, not a generic write-up.
How we build
Designed for the browser you already have
The test runs entirely on the web: fast loads, keyboard and touch input, and history that stays local unless you clear your browser data. We use lightweight analytics to see what helps players — never to gate results behind a profile. The engine on the home page is the one described on our guide pages, so search results and the live test never drift apart.
Play anywhere
Phone, tablet, and desktop share one layout. Tap the colour buttons on a touchscreen, or use number keys 1–6 on a keyboard for the cleanest reaction times.
History on your device
Best score, best accuracy, fastest reaction time, lowest interference, and your last twelve runs are stored locally. You own the continuity of your record without signing up.
Quiet improvement
We watch aggregate usage through Google Analytics to improve pacing and polish. Details are in our Privacy Policy — never as a sales pitch.
Contact
Stay in the loop
Feedback on a run length, a bug report, partnership ideas, or a simple hello — we read every message. Hit the button and we will get back to you.
Stay in TouchPrefer the fine print first? Our legal pages cover how the site works and how we handle analytics.