30 Second Timer
Free online 30 second timer with alarm. Perfect for exercise sets and quick breaks.
⏱️ 30 Second Timer: Start a free 30-second countdown timer instantly — no downloads, no sign-up. Just click Start.
Why use a 30-second timer?
30 seconds is the smallest timer interval most people consciously use. It's the standard high-intensity work block in HIIT, the ideal break for eye-rest, and the time it takes to brush each quadrant of your teeth properly.
What people use a 30-second timer for
HIIT work interval
The most common high-intensity interval — 30s all-out, then 30-90s rest.
Tooth brushing per quadrant
ADA recommends 2 minutes total — 30 seconds per quadrant of teeth.
Eye-rest micro-break
Look 20 feet away for 30 seconds every 20 minutes (the 20-20-20 rule, extended).
Hand washing
CDC recommends scrubbing for at least 20-30 seconds, the time it takes to sing "Happy Birthday" twice.
Plank entry-level
A 30-second plank hold is the beginner benchmark; you build from here.
The 30-second interval, in context
Half a minute is the threshold where focused intent becomes possible. Shorter than this and you can barely start; longer and you can complete most micro-tasks.
Halfway between the 15-second elevator pitch and the full 1-minute board-game turn.
About the 30 Second Timer
Free online 30 second timer with alarm. Perfect for exercise sets and quick breaks.
Related
Frequently asked questions
Why use a 30-second timer specifically?
30-second intervals are calibrated for high-frequency, repetitive cues — HIIT work bouts, plank holds, breath holds, hand-washing. The interval is short enough that you can repeat it many times in a single session, which is the whole point of micro-interval training.
Does the 30-second timer keep accurate time?
Yes. The 30-second countdown uses the browser's high-resolution monotonic clock (performance.now), accurate to sub-millisecond. For micro-intervals this matters — drift of even 1-2% would compound noticeably across a Tabata cycle of 8 rounds.
Can I chain multiple 30-second intervals together?
For repeated 30-second intervals (Tabata, plank circuits, breath-hold sets), look at the Fitness Timer or Tabata Timer instead — they handle work-rest cycles automatically. This page is set up for a single 30-second block. Restart manually for additional reps.
What happens when the 30-second timer reaches zero?
An alarm fires immediately and the display flashes. For 30-second intervals where you need to act quickly (HIIT transitions, breath-hold release), the audible cue is the active ingredient — make sure your device volume is up.