DataToolsLab
Date & Time Tools

Stopwatch & Timer

A precise browser stopwatch and countdown timer with lap support.

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What is Stopwatch?

A pair of timing tools: a start/stop/reset stopwatch with lap recording, and a countdown timer for a set number of minutes and seconds.

How it works

Elapsed time is computed from performance.now() deltas rather than accumulated ticks, so it stays accurate even if the tab is throttled.

  1. Enter your input. Type or paste your input into the field above — the tool responds instantly.
  2. Review the result. Output updates live as you type. Everything runs entirely in your browser.
  3. Copy or download. Use the Copy button to grab the result, or Download to save it as a file.

Examples

Elapsed-time tracking

Time a task or race with lap support — start, record a lap, and read precise split times without losing the running total.

Common mistakes

Losing time to tab throttling

Browsers throttle timers in background tabs. The stopwatch anchors to wall-clock time so the elapsed reading stays correct when you return.

Frequently asked questions

Can I record laps?

Yes — each lap captures the split time and the cumulative elapsed time since start.

Does it keep running if I switch tabs?

It keeps accurate elapsed time based on the clock, even though the display updates only while the tab is visible.

Is there a countdown mode?

No — for counting down to a target use the Countdown Timer; this tool measures elapsed time from start.

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