Stopwatch
Millisecond precision with lap tracking
When Milliseconds Matter
Stopwatches measure elapsed time, which sounds trivially simple until you need precision. A hand-timed 100-meter sprint has roughly 0.2 seconds of human reaction delay between seeing the finish and pressing the button. Electronic timing systems at the Olympics are accurate to 0.001 seconds — a margin that regularly determines gold versus silver. The difference between first and second place in the 2024 Olympic 100m final was 0.03 seconds.
In cooking, the difference between al dente and overcooked pasta is about 60-90 seconds. In photography, exposure times measured in fractions of a second determine whether an image is sharp or blurred. In music, tempo precision to within 1 BPM separates professional performances from amateur ones. Time measurement is one of those tools where "close enough" depends entirely on what you are measuring.
Lap Times vs Split Times
These terms are often confused but mean different things. A lap time measures the duration of a single segment — how long that specific lap took. A split time measures the cumulative time from the start to the current point. If you run a 400-meter track in four laps of 70, 72, 74, and 71 seconds, your lap times are those individual numbers and your split times are 70, 142, 216, and 287. This stopwatch shows both so you can track consistency and overall progress simultaneously.
Does the stopwatch work in the background?
Yes. The timer continues running even if you switch browser tabs or minimize the window. When you return, the display will show the correct elapsed time. This uses the system clock rather than a simple counter, ensuring accuracy regardless of browser focus.
How accurate is this stopwatch?
This stopwatch is accurate to approximately 1 millisecond, limited by browser rendering speed. For most practical purposes (cooking, workouts, presentations), this far exceeds the precision needed. For competitive sports timing, dedicated hardware timers with sensor triggers are required.