Countdown Timer

What is a countdown timer?

A countdown timer is a clock that runs backward from a duration you choose down to zero, then alerts you when the time is up. Unlike a stopwatch, which counts upward from zero to measure elapsed time, a countdown timer starts from a set amount of time and ticks down second by second. It's the digital version of a kitchen timer or an egg timer: you tell it how long you want, start it, and it lets you know the moment that time has passed so you don't have to keep checking the clock.

How to set a countdown timer

Setting and running the timer takes only a few seconds, and it begins counting the instant you start it:

1. Type the hours, minutes, and seconds you want, or tap a quick-set preset such as 5 or 25 minutes.
2. Press Start to begin the live countdown.
3. Use Pause to stop the clock and Resume to pick up where you left off, or Reset to clear it back to your set time.
4. When the timer reaches zero, the display flashes "Time's up!" and an alarm sound plays if the alarm option is on.

Countdown timer vs. stopwatch

A countdown timer and a stopwatch are opposites. A countdown timer starts from a duration you set — say 10 minutes — and counts down to zero, alerting you when time runs out; it answers "how much time is left?" A stopwatch starts at zero and counts up, measuring how long something takes; it answers "how much time has passed?" Use a countdown timer to limit an activity to a set length, and a stopwatch to time an activity of unknown length.

Will the timer keep running if I switch tabs?

Yes. The timer is based on real clock time, not on a simple per-second counter, so it stays accurate even if your browser slows background tabs down. When you come back to the tab, the remaining time reflects the actual time that has passed. For the alarm sound to play, keep the tab open, since browsers limit audio in inactive tabs; the visual "Time's up!" message will be waiting for you regardless.

Why use this countdown timer?

• Counts down live in hours, minutes, and seconds with a large, easy-to-read display.
• One-tap presets for 1, 5, 10, 15, and 25 minutes and 1 hour — great for Pomodoro and quick tasks.
• Start, pause, resume, and reset controls so you stay in full control of the clock.
• Flashes the display and plays an optional alarm sound the moment time runs out.
• Stays accurate using real clock time, even if the browser throttles a background tab.
• Runs entirely in your browser — no app to install and nothing is uploaded.
• 100% free with no ads, sign-up, or limits.

Frequently asked questions