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1 Hour Timer
Your one-hour countdown (1:00:00) is ready: press Start (or Space) and the alarm sounds after 60 minutes. Use the ±5 min buttons to adjust it and the halfway chime to know when 30 minutes are left.
1:00:00
Ready
Presets
Shortcuts: Space start / pause · R reset · F fullscreen. Add ?m=30 to the address for a custom length. Keep this tab open; the countdown stays accurate in the background.
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How to use the 1 Hour Timer
- Press Start or hit the Space bar. The 1:00:00 countdown begins immediately.
- Want a reminder midway? Tick Soft chime at the halfway mark to hear a gentle chime at 30:00 left.
- Fine-tune the length with the ± buttons or pick another preset.
- Choose an alarm sound and volume, then press Play test sound to check you can hear it.
- When time is up, press Stop alarm or Space. Press R to reset to 1:00:00.
How long is 1 hour?
| Measure | 1 Hour equals |
|---|---|
| Minutes | 60 min |
| Seconds | 3,600 s |
| Milliseconds | 3,600,000 ms |
| Hours | 1 h |
| Share of a day | 4.17% (1/24 of a day) |
| Walking at 5 km/h (3.1 mph) | about 5 km (3.1 mi) |
| Speaking at 130 words per minute | about 7,800 words |
| Reading at 230 words per minute | about 13,800 words |
What you can do in 1 hour
| Activity | Why 1 hour works |
|---|---|
| Exam or test | Many exams and timed assessments last one hour |
| Cooking | Roast chicken pieces, slow-baked dishes and bread proofing |
| Meeting | Keep a one-hour meeting on schedule |
| Screen-time limit | A clear end point for games or videos |
| Laundry cycle | Many washing machine programs run about an hour |
| Workout | A full training session including warm-up and cool-down |
How the countdown keeps exact time
When you press Start, the timer records the end moment as start time + 3,600,000 ms on the browser's monotonic clock (performance.now()). Every screen update subtracts the current time from that end moment instead of counting ticks, so a throttled background tab or a busy computer cannot make it fall behind. Pausing stores the time left, and Resume sets a new end moment that far in the future.
Frequently asked questions
How do I set a 1 hour timer?
It is already set to 1:00:00. Press Start or the Space bar; when the hour is up the alarm rings until you stop it.
How many seconds are in 1 hour?
One hour is 60 minutes, 3,600 seconds or 3,600,000 milliseconds.
Why does the display show 1:00:00?
Times of an hour or more are shown as hours:minutes:seconds. Once less than an hour is left it switches to minutes:seconds, for example 59:59.
Can I adjust the timer?
Yes. The −5 min and +5 min buttons change it in 5 minute steps, the presets go from 15 minutes to 2 hours, and ?m=75 in the address opens a 75 minute timer.
Will it stay accurate for a whole hour?
Yes. The timer stores the exact end moment and recalculates the time left from the clock, so background tabs and a busy computer cannot make it run slow. Keep the computer from sleeping.
Can I get a notification instead of sound?
Yes. Tick "Notify me when time's up" and allow notifications; you will get a desktop notification when the hour ends.
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