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Stopwatch and Countdown Timer

A stopwatch with laps and a countdown: wall-clock math that survives background throttling, memory-only.
in-memory only · wall-clock deltas survive background throttling · nothing is storedStopwatchCountdown

00:00.00

0 ms total
StartLapReset

- Elapsed time is recomputed from wall-clock deltas, never accumulated from display ticks, a backgrounded or throttled tab keeps the right total because the math reads the clock, not the callbacks.
- State lives in memory on this page only: reloading, closing, or navigating clears it. Nothing is written to any storage.
- The display refreshes about 20× per second while running; the centiseconds shown are real wall-clock math, not interpolated.
- Countdowns are capped at 24 hours. This is a timer for people, not a scheduler.
Nothing in yet

Paste, drop, or type to begin. Everything stays on this device.

state is memory-only: it lives exactly as long as this page does

Next door in Time

- Timestamp converter (/time/timestamp-converter)
- Duration converter (/time/duration-converter)
All time tools (/time)

Canonical HTML: https://nutter.tools/time/stopwatch
Markdown version: https://nutter.tools/time/stopwatch/index.md
Plain-text version: https://nutter.tools/time/stopwatch/index.txt
Agent index: https://nutter.tools/llms.txt