Stopwatch vs countdown timer: when to use each
A stopwatch counts up from zero to measure how long something actually takes — a coding session, a workout, a test run. Its lap feature records split times without stopping the clock, and this tool highlights your fastest lap in green and slowest in red so patterns jump straight out. A countdown timer counts down to zero to enforce a limit — a presentation slot, an exam, a cooking step. The progress bar and browser-tab countdown let you stay aware of the time remaining without staring at the numbers.
Accurate timing that survives a busy browser
This timer runs on requestAnimationFrame, which stays locked to your display refresh rather than drifting the way setInterval does under CPU load, keeping it accurate to a millisecond or two. Loop mode restarts the countdown automatically for repeating intervals, fullscreen turns it into a room-visible clock, and an optional desktop notification plus a Web Audio alarm make sure you're alerted the moment it reaches zero — even from another tab.
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- Millisecond precision via requestAnimationFrame (drift-free)
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- Lap tracking with automatic fastest/slowest split highlighting
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- Loop mode for repeating intervals and HIIT rounds
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- Countdown mirrored in the browser tab title
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- Fullscreen mode for presentations and classrooms
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- Desktop notification plus Web Audio alarm at zero
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- Keyboard shortcuts (Space, L, R) — no app or download
