3 Second Timer
Free online 3 second countdown timer with alarm
A three second timer for a 3-2-1 countdown before a recording, a race start, or a photo. Big digits, an alert at zero, and nothing to set up.
Space start/pause · R reset · +− adjust
Floating Picture-in-Picture needs a Chromium browser; this one doesn't support it.
Background sound
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More ways to run this timer
Proven Timer Pages
Build repeating work and rest rounds in the Interval Timer →Related Timers
Embed this timer
Paste this into any page — a class blog, a lesson plan, a meeting agenda — and visitors get a working 3 second timer with no script tag, no account and no tracking. Please keep the credit link.
About the 3 Second Timer
A 3 second timer that starts the moment you press Start, with big digits you can read from a distance and a beep at zero. No ads, no signup, nothing to install.
TimerHub calculates remaining time from an absolute finish timestamp, so missed browser callbacks do not create drift. Read the timing accuracy methodology and reproducible tests.
Common Uses
- Rest between exercise sets
- Sprint or exercise rep
- Game countdown
- Reaction time test
- Breathing reset
How to Use the 3 Second Timer
- Click Start (or press Space) to begin your 3 second countdown
- Press Space again to pause and resume, or R to reset the timer
- Use the +/- buttons to adjust by 10 seconds while running
- Toggle Repeat to loop the countdown automatically, and watch the finish time under the display
- Use the Fullscreen control below the timer for a large full-screen countdown (Esc to exit)
- Pick a background sound — rain, ocean, fireplace or brown noise — that fades out at zero
- Choose or mute the alarm sound from the sound settings in the header
- Add
?autostart=1to the link to start the countdown on load - Enable notifications for alerts when your 3 second timer finishes, even in a background tab
Frequently Asked Questions
How long is 3 seconds?▾
3 seconds is less than a minute. Our free 3-second timer gives you a precise countdown with an alarm at the end.
What can I use a 3 second timer for?▾
A 3 second timer is perfect for rest between exercise sets, sprint or exercise rep, game countdown. Hit Start and the countdown begins instantly.
Does the timer work in the background?▾
Yes, our timer continues running even if you switch to another tab or minimize your browser. Enable notifications to get alerted when it finishes.
Does the alarm sound when the timer finishes?▾
Yes, an alarm plays automatically the instant the 3 second countdown hits zero, with an optional vibration on mobile. Enable notifications for an extra alert in background tabs.
Can I make the timer fullscreen?▾
Yes, use the Fullscreen control below the timer to show a large full-screen countdown that is easy to see across a room or gym. Press Esc to exit fullscreen.
Can I use this 3 second timer on mobile?▾
Yes, our 3 second timer works on all devices including phones and tablets. No app download needed — just open this page in your mobile browser.