Countdown Timer
Drift-free online countdown timer with presets, custom durations, and sound alert.
05:00
Quick Presets
Note: This timer uses system timestamp reconciliation to prevent interval drift when tab is inactive. Keep tab active for audible notifications.
How to Use Countdown Timer
- Choose a quick preset or type a custom minute and second duration.
- Click Start to begin countdown. Calculations use wall-clock timestamps to eliminate interval drift.
- Audio chime plays automatically upon reaching zero.