Chronometer

This chronometer is a simple online stopwatch. It measures elapsed time with millisecond display and lets you record lap or split times, which is useful for timing workouts, speeches, cooking steps, manual tests or how long a process takes.

How to use it

1. Press start to begin timing.
2. Press lap to record an intermediate time without stopping.
3. Pause to freeze the time, resume to continue, or reset to clear it.

Lap time vs. split time

A split time is the total elapsed time when you press the button. A lap time is the time since the previous lap. For example, if you record marks at 1:05, 2:08 and 3:15, the splits are those three values and the laps are 1:05, 1:03 and 1:07. Comparing laps shows whether your pace is consistent.

How accurate is a browser stopwatch?

The timer is based on the system clock through performance.now() or Date.now(), not on counting animation frames, so it stays accurate even if the display updates less often. Human reaction time when pressing start and stop is typically 0.15 to 0.25 seconds, which is much larger than any software error. For official sports timing, use certified equipment.

Tips

• Keep the tab open. Some browsers slow down timers in background tabs, but elapsed time is still calculated correctly when you return.
• Use the keyboard to start and stop if available; it is faster than clicking.
• For countdowns, use the countdown or Pomodoro timer instead.