Time Tools
Start, lap, and reset — a straightforward stopwatch with split times, accurate to the centisecond.
Each lap records the time since the previous lap (or since starting, for the first one) alongside the running total — the two numbers you actually need to see whether a particular segment was faster or slower than the ones around it. The stopwatch keeps running in the background between laps; hitting "lap" doesn't pause anything.
Like the Pomodoro Timer, this runs entirely in the current browser tab and resets if you navigate away.
Related
Structured focus/break intervals instead of free-running elapsed time.
Work out a duration from two clock times instead of timing live.
Check the current time in any major city.