15 Second Timer
Free online 15 second countdown timer with alarm
Space start/pause · R reset · ↑↓ adjust
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About the 15 Second Timer
Free online 15 second timer with alarm sound. Start instantly — perfect for exercises, game countdowns, cooking, and speed challenges. No signup required.
Common Uses
- Quick exercise rep
- Game countdown
- Speed challenge
- Reaction time test
How to Use
- Click Start to begin your 15 second countdown
- Use the +/- buttons to adjust by 10 seconds while running
- Press Space to start/pause, R to reset your timer
- Enable notifications for alerts when your 15 second timer finishes
Frequently Asked Questions
How long is 15 seconds?▾
15 seconds is less than a minute. Our free 15-second timer gives you a precise countdown with an alarm at the end.
What can I use a 15 second timer for?▾
A 15 second timer is perfect for quick exercise rep, game countdown, speed challenge. 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.
Can I use this 15 second timer on mobile?▾
Yes, our 15 second timer works on all devices including phones and tablets. No app download needed — just open this page in your mobile browser.