Stopwatch & Countdown Timer

The stopwatch uses performance.now() which provides sub-millisecond precision. Display updates every 50ms. Accuracy is typically within a few milliseconds for most use cases, though very long-running timers may drift slightly due to browser tab throttling when the tab is in the background.

Modern browsers throttle JavaScript in background tabs, so the alarm may fire a few seconds late if you switch to another tab. For time-critical alarms, keep this tab in the foreground. The alarm uses the Web Audio API to play a beep sound directly in your browser — no external resources needed.

The Pomodoro Technique uses 25-minute focused work sessions followed by 5-minute breaks. Click the "25 min" preset to set the countdown, start it, and take a 5-minute break when the alarm fires. After 4 Pomodoros, take a longer 15–30 minute break.