Free Online Stopwatch & Countdown Timer With Alarm
From timing study sprints and gym rests to cooking pasta and running meetings, everyone needs a timer that is already open. This free page pairs a hundredth-second stopwatch with lap capture and a countdown timer with a WebAudio triple-beep alarm and tab-title flash — no app install, no account, works offline once loaded.
How to Use Both Timers
- Stopwatch: Start/Pause with one button, tap Lap to freeze split times without stopping, Reset to clear. Splits list newest-first for easy reading.
- Countdown: enter minutes and seconds, Start, and keep the tab open — at zero the alarm sounds three beeps and the browser tab title flashes.
- Multitask safely: the title flash means you will notice completion even buried in twenty tabs.
Accuracy Notes Worth Knowing
Browser timers update on 31 ms ticks for the stopwatch display (hundredths need ~10 ms granularity, and 31 ms keeps CPU near zero), while elapsed math uses Date.now() differences, so displayed digits may skip but totals stay exact to the millisecond. Countdown ticks once per second; background tabs may throttle timers in some browsers, so keep the page visible for mission-critical timing like exams. The alarm uses the WebAudio API — no audio files, no autoplay-blocker games beyond requiring your initial Start click.
Does the alarm work if I switch tabs?
Yes — audio continues in background tabs, and the flashing document title catches your eye on return. Very long background throttling can delay ticks slightly, so keep critical countdowns in a visible tab.
Can I time hours-long events?
Yes. The stopwatch counts indefinitely (MM:SS.cs rolls past 59 minutes), and laps scroll in their own box. For multi-hour tracking, note the start wall-clock time as backup.
Is anything recorded?
No — times live in page memory only. Refresh and everything resets, which is also why nothing can leak.
Related Tools
Schedule across zones with the Time Zone Converter, test reactions with the Time Perception Test, and measure speed with the Typing Speed Test.