Online stopwatch
Start, stop, reset and record lap times with tenth-of-a-second precision. It keeps counting even if you switch tabs.
Why it stays accurate in background tabs
When a tab goes into the background, browsers throttle internal timers to save battery, so a poorly built stopwatch "loses" seconds. This one doesn't count ticks one by one: it stores the moment you pressed Start and computes elapsed time as the difference between real timestamps. You can switch tabs, minimize the window or lock your phone's screen, when you come back, the time shown will still be correct.
How to use lap times (splits)
The "Lap" button records two values: the lap time (how long since the previous split) and the total time since the start. It's the classic way to time workouts: during track intervals, the lap time tells you whether you're holding your pace, while the total gives you a projection of your finish. It works just as well in the kitchen, for interval study sessions, or for timing the sections of a presentation, when you're done, copy all your splits with one click and paste them anywhere.