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1 hour timer

1:00:00

Press Start or the space bar.

Settings

1 hour at a glance

On the timer
1:00:00
Seconds
3,600
Minutes
60
Hours
1
ISO 8601 duration
PT1H
Share of a day
4.17 %
Back to back in one hour
1
Back to back in 24 hours
24

When a 1 hour timer ends

The line under the timer shows the end time for your clock as soon as the page opens. For planning, here is where 1 hour lands from some common start times:

StartEnds
7:00 AM8:00 AM
9:00 AM10:00 AM
12:00 PM1:00 PM
3:30 PM4:30 PM
5:45 PM6:45 PM
10:30 PM11:30 PM
11:50 PM12:50 AM (next day)

1 hour is longer than many computers’ and phones’ sleep settings. A sleeping device runs no web pages, so plug in and keep the screen on for this one. If the device does sleep, the timer is still right when it wakes, because it counts down to a fixed end time instead of counting ticks, and it rings at once if that time has passed.

A daylight saving change does not shorten or lengthen the timer: it measures 1 hour of real time. What changes is the clock reading at the end. On the night clocks go back an hour (2:00 AM daylight time becomes 1:00 AM standard time in the US), a 1 hour timer started at 1:30 AM ends when the clock shows 1:30 AM, not one hour later. If you need something to happen at a clock time, use an alarm instead.

Questions

How do I set a timer for 1 hour?
This page is already set to 1:00:00. Press Start, the space bar or Enter. It rings after exactly 1 hour; you can add or remove a minute while it runs with + and −.
How many seconds is 1 hour?
1 hour is 3,600 seconds or 60 minutes. In ISO 8601 notation, the standard way software writes a duration, it is PT1H.
Will a 1 hour timer survive my computer going to sleep?
No web page can run while the computer sleeps. 1 hour is longer than many power-saving settings, so plug in and set sleep to “never” for this run. If the computer does sleep, the timer shows the right time again when it wakes, and rings at once if the end time has passed.

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