Countdown Timer
Choose a preset or set hours, minutes and seconds. Start a countdown for study, cooking or a short break.
Keep this tab open. Device sleep or browser suspension can delay the alarm.
How to use it
Choose a duration and press Start. Pause preserves the remaining time. Reset returns to the configured duration. Turn Alarm sound on before starting for an audible alert.
Useful example
Choose the 25-minute preset for a focused study session. When the time reaches zero, the page shows Time is up and plays a short alarm if sound is enabled.
Tips
The countdown uses a target timestamp to avoid accumulating drift. Sleeping devices, closed tabs and suspended browsers cannot reliably deliver alarms; keep this page open and your device awake.
Frequently asked questions
Does this tool upload my inputs?
No. The calculation or conversion happens on your device. You do not need an account.
Can I use it on a phone?
Yes. The controls adapt to smaller screens and work with touch and keyboard input.
What should I know about the result?
The countdown uses a target timestamp to avoid accumulating drift. Sleeping devices, closed tabs and suspended browsers cannot reliably deliver alarms; keep this page open and your device awake.
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Last updated . Formulas are shown on the page and checked against the worked example.
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