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Everyday tool

Alarm Clock

Set an online alarm with hours, minutes, seconds, and presets. Visual Done state plus a soft alert—runs in your browser.

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How to use

Follow these steps for a clear answer.

1

Set the duration

Enter hours, minutes, and seconds, or tap a preset (1 / 5 / 10 / 25 min).

2

Start

Start the countdown; a soft alert plays when time reaches zero.

3

Pause or reset

Pause to hold remaining time, or Reset to reload your inputs.

Alarm clock specification

Version 2.0.0 · Last reviewed 2026-07-28

Definition
An online alarm here is a countdown to a chosen delay, ending with a Done state and optional local sound.
What it calculates
Remaining time until a user-chosen delay elapses, then Done.
Inputs
  • Hours, minutes, seconds or minute presets
  • Start / Pause / Reset
Outputs
  • Live remaining time
  • Done state with optional beep
Formula
remaining = max(0, endAt − now)

Use the Alarm Clock as a quick browser timer: set how long until the alert, press Start, and get a Done state when time is up. Presets cover common focus blocks; hours and seconds are available for longer or precise delays.

This is ideal for study breaks and kitchen timers when you can leave the tab open—not a system-level alarm that fires with the screen locked.

Assumptions
  • Same local countdown engine as the Countdown Timer tool.
  • Requires an open tab for a reliable on-page alert.
Units
  • Delay: hours, minutes, seconds
Boundary conditions
  • Zero delay completes immediately when started.
  • Locked screens or closed tabs may miss the sound.
Example
25 min preset → Start → Done after twenty-five minutes
Validation cases
  • Start with 1 min → Done after about one minute
  • Pause → Delay extends by pause duration
Sources
  • Browser Date.now() countdown with optional Web Audio beep
Last reviewed
2026-07-28
Calculation version
2.0.0
→ Countdown Timer › → Stopwatch › → Current Time › → Today's Date ›

Frequently asked questions

Key distinctions behind the tool.

How does this alarm work?

You set a countdown duration. When remaining time hits zero, the display shows Done and a short sound may play.

Can I set hours as well as minutes?

Yes. Use hours, minutes, and seconds, or tap a minute preset.

Will it wake my phone if the screen is locked?

No. Keep the browser tab open and the device unlocked if you need the on-page alert.

Is this a repeating daily alarm?

This page is a one-shot countdown alarm. Start again with a new duration for the next reminder.

Is anything sent to a server?

No. Timing runs locally in your browser.