Timer, Stopwatch & Countdown

about this tool

Three clocks

Stopwatch counts up in hundredths, with laps: each lap's time, the total at that point, the difference from the previous lap, and the fastest and slowest marked. Laps copy as tab-separated text for a spreadsheet.

Timer counts down from a duration typed as a clock (25:00, 1:30:00), with units (90s, 1h 20m) or as minutes, or picked from the presets. It shows whole seconds rounded up, so 00:01 always means there is time left. When it ends it beeps three times and, if you have ticked "Notify me" and allowed it, posts a system notification that reaches you in another tab.

Countdown to a date counts down to a moment you pick in your own time zone, in days, hours, minutes and seconds.

Exact in a background tab

Browsers throttle timers in hidden tabs, so a clock that adds a second every tick falls behind. Here nothing is counted: the moment you pressed Start is recorded, and the display is worked out from the clock each time it is drawn. A tab that was asleep for ten minutes shows the right time the instant it wakes, and a timer that ended while hidden fires as soon as the tab is allowed to run.

Sharing

The site keeps nothing in your browser, so a timer is carried in the address instead. Copy link on a countdown produces ?until= followed by the target instant, which opens as the same countdown in anyone's time zone; on a timer it produces ?d= followed by the length in seconds, which opens ready to start. Anything else in the address is left alone.

Limits

The beep uses the browser's audio and may be silent until you have interacted with the page, which the browser requires; the notification depends on permission you grant in the browser, not here. Laps and a running stopwatch are lost if you close the tab, by design, since nothing is stored. The countdown updates once a second; the stopwatch and timer twenty times a second, which is plenty for a display and gentle on a laptop battery.

For a countdown to a fixed date rather than a duration, date difference & duration gives the interval. If the deadline is in someone else's zone, the time zone converter will place it.

questions

Does the timer keep going if I switch tabs?

Yes. Browsers slow down timers in background tabs, so a timer that counts ticks drifts. This one records the moment it started and works out the time from the clock whenever it draws, so when you come back it is exactly right, and the alarm fires as soon as the tab is allowed to run again.

Will it notify me when the timer ends?

It beeps, and if you tick “Notify me” and allow notifications when the browser asks, it also shows a system notification, which reaches you when the tab is hidden. The permission is the browser’s; the site stores nothing.

How do I share a countdown?

Copy link puts the target moment into the address, so anyone who opens it sees the same countdown in their own time zone. A timer link carries the length instead and opens ready to start. Nothing is stored anywhere; the link is the whole state.

How do I type a duration?

As a clock (25:00, 1:30:00), with units (90s, 1h 20m, 5 minutes), or as a bare number of minutes. Presets cover the common ones.

Why does the stopwatch show hundredths but the timer whole seconds?

A stopwatch is for measuring, and hundredths are what a hand stopwatch shows. A timer is for waiting, and it rounds up: 00:01 means there is still more than a second left, so it never reads 00:00 while time remains.