A countdown timer is a clock that counts down from a set length of time to zero. When it reaches zero, it signals the end with a sound or a change on the display.
Online Countdown Timer
This timer counts down from the time you set, turns red for the last 10 seconds if you want, and plays a beep when it reaches zero.
Quick set
05:00
Ready
The sound follows your device's volume and silent mode.
The timer stops if you close or reload this tab.
How to use the timer
- Type the hours, minutes and seconds, or press a quick-set button such as 5 min.
- Choose whether the last 10 seconds turn red and whether a sound plays at the end.
- Press Start. The large number counts down and the browser tab title shows the time left.
- Press Pause to hold the timer, Resume to continue, or Reset to go back to the time you set.
What is a countdown timer?
How a countdown timer works
- A timer shows the time left, and a stopwatch shows the time that has passed. A timer goes down from the set time to zero, and a stopwatch starts at zero and goes up.
- A timer measures a length of time, not a time of day. An alarm clock rings at a set time such as 3:00 p.m., and a timer rings 10 minutes from now.
- The set time is counted in seconds. One minute is 60 seconds and one hour is 3,600 seconds, so 1 hour 15 minutes 30 seconds is 4,530 seconds.
- The time left is written as hours, minutes and seconds with colons between them. 05:00 means 5 minutes, and 01:30:00 means 1 hour 30 minutes.
When a countdown timer helps
- Timing a presentation, a speech or a meeting agenda item so the speaker sees the last 10 seconds.
- Running a 25-minute focus session and a 5-minute break while you study or work.
- Timing a mock exam, a quiz or a classroom activity on a shared screen.
- Cooking pasta, steeping tea, or timing a workout set and a rest interval.
Questions about the timer
Does the timer keep running when I switch to another tab?
Yes. The timer calculates the time left from the moment it will end, so it does not fall behind when the browser slows a background tab. The tab title shows the time left. The end sound is scheduled when you press Start, so it plays on time in a background tab. A phone may suspend the browser when the screen locks, so keep the screen on for long timers.
Why can't I hear the sound when the timer ends?
Check that the sound switch is on, that the device volume is up, and that the browser tab is not muted. Browsers only allow sound after you press something on the page, so the timer prepares the sound when you press Start. An iPhone in silent mode does not play it.
What is the longest time I can set?
99 hours, 59 minutes and 59 seconds. The minutes and seconds boxes accept numbers of 60 or more: 90 in the minutes box means 1 hour and 30 minutes.
Can I turn off the red background?
Yes. Turn off “Highlight the last 10 seconds in red”. When the switch is on, the time box turns red when 10 seconds are left and stays red after the timer ends, so you can see that time is up from across the room.
Are my settings saved?
The two switches and the last time you started are saved in this browser's local storage. Nothing is sent to a server. A running timer is not saved: it stops if you close or reload the tab.