How is the error calculated?

We measure the time from pressing Start to pressing Stop and compare it with the target in ms. Early or late, only the size of the difference counts, and anything more than a second off counts as 999ms.

Why do the numbers vanish at different times?

It depends on the difficulty: 5 seconds on Easy, 3 on Normal, 1 on Hard, and never on Master. The longer you see them, the easier it is to keep the beat.

What happens if I hit it exactly?

An error of 10ms or less shows “Spot on!”, and doing it once earns the “Dead On 10” achievement.

Stop at 10 Seconds — even when the numbers vanish

Press start, watch the stopwatch count up, then keep counting when the numbers disappear. Stop when you think it is exactly 10 seconds, and the difference is recorded in ms. Rankings use the average error over 3 rounds, and Master changes the target to 5–15 seconds.

About the game

Stop at 10 Seconds is a time sense game: after the stopwatch numbers vanish, stop at exactly 10 seconds by feel. A game has 3 rounds, and your record is the average difference (error) between your stops and the target.

How to play

Press Start or the Space bar and the stopwatch starts counting.
After a few seconds the numbers vanish. Keep counting in your head and press again when you think the target time is reached.
The difference between your stop and the target (the error) is recorded. The smaller the average error over 3 rounds, the better.
On Master the numbers never show, and the target changes every round between 5 and 15 seconds.

Difficulty

Easy: Numbers show for the first 5 seconds
Normal: Numbers show for only the first 3 seconds
Hard: Numbers vanish after just 1 second
Master: No numbers at all, and the target is 5–15 seconds

Tips

While the numbers are visible, feel how long one second is. Keeping the same beat after they vanish is the key.
Counting with longer words, like “one Mississippi”, keeps your beat from speeding up.
Nerves make you count faster. If you tend to stop early, wait half a beat at the end before pressing.

Records and leaderboard

Your best score for each difficulty stays in this browser even without signing in. Sign in and every finished game is saved to your account, and you can compete with other players on the leaderboard in My results. Only your nickname is shown on the leaderboard.

Frequently asked questions

How is the error calculated?: We measure the time from pressing Start to pressing Stop and compare it with the target in ms. Early or late, only the size of the difference counts, and anything more than a second off counts as 999ms.
Why do the numbers vanish at different times?: It depends on the difficulty: 5 seconds on Easy, 3 on Normal, 1 on Hard, and never on Master. The longer you see them, the easier it is to keep the beat.
What happens if I hit it exactly?: An error of 10ms or less shows “Spot on!”, and doing it once earns the “Dead On 10” achievement.