Online timer

Q: How do I set a timer until 6 PM (or any time of day)?

Choose Until a time and pick the time. The timer counts down to the next time your clock shows it: today if it is still ahead, otherwise tomorrow. If a daylight saving change falls in between, the countdown includes the extra or missing hour, because it counts real elapsed time.

Q: Can I run a timer with no sound?

Yes: set the volume slider to zero or press M to mute. The display blinks and the tab title shows “Time’s up!” when it ends.

Q: Can I make an interval (Tabata-style) timer?

Choose Intervals and set the work time, the rest time and the number of rounds, for example 20 seconds of work, 10 seconds of rest, 8 rounds. A short beep marks each change and the full sound plays at the end.

5:00

Press Start or the space bar.

How to use the timer

Any duration, typed the way you think

The Time box understands what you type: 5 means five minutes, 90s is ninety seconds, 1h30m, 1.5h and 1:30:00 are all an hour and a half, and 2 hours 15 minutes works too. The line below the box confirms how it read your entry before you start. The longest timer is 99 hours, 59 minutes and 59 seconds.

The quick-start buttons start a timer in one click. While a timer runs, +1 min and −1 min (or the + and − keys) adjust it without a restart, and Restart runs the same timer again from its full time in one tap (also after it has rung, while the clock counts the time since zero).

Count down to a time of day

Many people search for a “timer until 6 PM” or “timer for 5:30”. That is a different calculation: the length depends on the time now. Choose Until a time, pick the time, and the timer works out the duration and counts down to it. If the time has already passed today, it counts to that time tomorrow. Times that a daylight saving change skips are handled too: the timer ends as if the clocks had not moved, which reads one hour later on the new clock (2:30 becomes 3:30).

Intervals

The Intervals mode alternates work and rest for a number of rounds: a short double beep marks each change, the display shows the round, and the full sound plays when the last work period ends. The hint line shows the total length before you start.

Sound, title and notifications

Five sounds are built into the page (they are generated by your browser, not downloaded), with a volume slider and a test button. The tab title shows the time left, so you can follow the countdown from another tab, and Notify me adds a system notification if you allow it. By default the timer rings until you stop it, for at most five minutes.

Keyboard shortcuts

Space: Start, pause, resume; stops the ring
Enter: Start from the Time box
R: Reset
+ or ↑: One minute more
− or ↓: One minute less
F: Full screen
M: Mute or unmute
Esc: Stop the ring

Why this timer stays accurate

A web timer that counts “one second, another second” drifts. Browsers deliberately slow scripts in background tabs to save battery, and a busy computer delays them further, so a ticking counter falls behind. This timer instead records the moment it should end and, at every refresh, shows the difference between that moment and now. However late a refresh comes, the number it shows is right.

“Now” comes from the browser’s monotonic clock, which only moves forward, corrected against our time server when the page loads. Changing the device clock, or the device correcting itself while the timer runs, therefore does not change the countdown.

The sound is the other weak point of web timers, because a throttled tab can notice the end late. When you press Start, this timer books its ring on the browser’s audio clock, which runs on its own thread and is not throttled, so the sound starts at the end time even if the page’s scripts are asleep.

A running timer is saved in your browser’s local storage. Reload the page, or close the tab and open the timer again, and it carries on (or rings, if its end has passed). The page needs no connection once it has loaded, and the timer itself is never sent anywhere.

Timer, alarm or stopwatch?

Tool	You give it	It measures	Across a clock change
Timer	A length of time	Elapsed time, down to zero	Still lasts exactly as long; the end shows a different clock time
Timer “until a time”	A time of day	Elapsed time until that clock time	Includes the extra or missing hour
Alarm	A time of day	Nothing: it waits for the clock	Rings when the clock shows the time; a skipped time rings just after the gap
Stopwatch	Nothing	Elapsed time, up from zero	Unaffected

To find out what time it will be after a duration, or how long it is until a time without starting anything, use the time calculator.

Phones, sleep and other limits

Phone browsers pause a page as soon as the screen locks or you switch apps. A paused page cannot play a sound, so on a phone keep the screen on and the browser in front while the timer runs; for a timer you will walk away from, the phone’s own clock app is the safer choice. The countdown itself is never wrong when you come back, because it is computed from the end time.

Browsers block sound until the visitor has interacted with the page. Starting the timer with a click or a key press counts, which is why a timer opened from a link waits for you to press Start instead of starting on its own. A computer that goes to sleep stops every web page; for long timers, check the power settings.

Ready-made timers

Questions

How do I set a countdown timer?

Type the duration in the Time box (for example 25 for 25 minutes, 90s, 1h30m or 1:30:00) and press Enter or the space bar, or click one of the quick-start buttons. The timer starts at once and rings when it reaches zero.

How do I set a timer until 6 PM (or any time of day)?

Choose Until a time and pick the time. The timer counts down to the next time your clock shows it: today if it is still ahead, otherwise tomorrow. If a daylight saving change falls in between, the countdown includes the extra or missing hour, because it counts real elapsed time.

Will the timer ring if I switch to another tab?

Yes. When you start it with a click or a key press, the ring is booked on the browser’s audio clock, which keeps running in background tabs. The countdown in the tab title keeps updating too, so you can watch it from another tab.

Does it work on a phone with the screen locked?

Not reliably. Phone browsers pause web pages when the screen locks or the browser goes to the background, so no web timer can promise a sound then. Keep the screen on, or use the phone’s built-in clock app for that case. When you come back, the countdown is still correct, because it is computed from the end time.

Can I run a timer with no sound?

Yes: set the volume slider to zero or press M to mute. The display blinks and the tab title shows “Time’s up!” when it ends.

Can I make an interval (Tabata-style) timer?

Choose Intervals and set the work time, the rest time and the number of rounds, for example 20 seconds of work, 10 seconds of rest, 8 rounds. A short beep marks each change and the full sound plays at the end.

Is anything sent to a server?

No. The timer runs in your browser. Its state is kept in your browser’s local storage so that a reload does not lose a running timer; nothing about it leaves your device.