Stopwatch & Timer

Stopwatch with lap tracking, countdown timer with alarm, and an interval timer.

Hours

Minutes

Seconds

Quick:

Interval Timer

Add intervals below to run a sequence of timed steps back-to-back, or send splits from the Pace Calculator.

Label

min

sec

00:00.00

Ready-made timers

One page per duration — open it and press start

10s 20s 30s 45s 1 min 2 min 3 min 4 min 5 min 6 min 7 min 8 min 10 min 12 min 15 min 20 min 25 min 30 min 40 min 45 min 50 min 1 hr 1h 30m 2 hr

The stopwatch uses performance.now() — a high-resolution monotonic clock — combined with requestAnimationFrame for smooth display updates. Because the elapsed time is computed as a delta from a reference timestamp (not by summing ticks), timing stays accurate even when the tab is backgrounded or the frame rate drops.

The countdown timer alarm uses the Web Audio API to synthesize three short beeps directly in the browser — no audio files needed.

The interval timer runs a sequence of timed steps back-to-back: each step counts down, beeps, and auto-advances to the next, so you can time a circuit workout, a set of running splits, or any repeating routine without touching the timer between steps. Add steps by hand, or send a splits sequence straight from the Pace Calculator.

Link to this tool with values filled in

Everything after the # stays in your browser — it is never sent to a server — so a link like this opens the tool ready to go without the values travelling anywhere but the address bar:

https://crunchify.net/tools/stopwatch-timer#minutes=10

Join the settings with &, and percent-encode each value so that spaces, newlines and any #, &, = or % inside one do not break the link. Leave a setting out to accept its default. If a setting is not recognised, the page says so rather than quietly ignoring it.

hours (also h) — a whole number from 0 to 99, defaults to 0. Hours on the countdown.
minutes (also m or mins) — a whole number from 0 to 59, defaults to 5. Minutes on the countdown. The page opens on 5 when no link says otherwise.
seconds (also s or secs) — a whole number from 0 to 59, defaults to 0. Seconds on the countdown.

How accurate is the stopwatch?

The stopwatch uses performance.now(), a high-resolution monotonic clock accurate to sub-millisecond precision. Displayed time is computed as a delta from a reference timestamp, not by summing ticks — so accuracy is maintained even if the tab is backgrounded or the frame rate drops.

Will the countdown timer alarm play if the tab is in the background?

Most browsers throttle or suspend JavaScript timers in background tabs, which can delay the alarm trigger. Keep the tab visible or prevent your browser from suspending it. The timer continues counting (the reference timestamp is preserved), but the alarm may fire a few seconds late.

Can I run the stopwatch and timer at the same time?

Yes — both run independently on the same page. Start the timer, then start the stopwatch; they use separate animation loops and do not interfere with each other.

What is the interval timer for?

The interval timer runs a list of timed steps one after another — each counts down, beeps, and automatically starts the next. It is useful for circuit or HIIT workouts, running splits, cooking stages, or any routine with several timed segments. Use Skip to jump to the next step, or Pause to hold the current one.

How do I load running splits into the interval timer?

Open the Pace Calculator, enter your distance and pace (or time), and click "Send to timer" above the splits table. Each split segment becomes an interval step, so the timer beeps as you reach each checkpoint at your target pace.

Updated October 8, 2026