A lap time is how long one segment took. A split time is the total time from the start up to that point. Run four laps of 1:32, 1:35, 1:37 and 1:30 and your splits are 1:32, 3:07, 4:44 and 6:14. Most stopwatches, including ours, show laps, so you get splits by adding the laps together as you go.
People mix these words up, but most running and swimming coaches use them like this.
Both come from the same button presses. The difference is just what you subtract. A lap is "this press minus the last press". A split is "this press minus the start".
Laps tell you about consistency. Splits tell you where you stand against a goal. If you're chasing a 6:00 mile, you want to see 1:30, 3:00 and 4:30 on your splits. To see if you faded, look at the laps.
Our online stopwatch has three buttons, and it works the same way as a sports watch.
Lap is disabled while paused, so you can't log one by accident during a break. Each row shows time since the previous lap, not the running total.
Add each lap to the running total. Here's the four-lap example from above, run on a standard 400 m track, with the pace each lap works out to.
| Lap | Distance so far | Lap time | Split (cumulative) | Mile pace for that lap |
|---|---|---|---|---|
| 1 | 400 m | 1:32 | 1:32 | 6:10 /mile |
| 2 | 800 m | 1:35 | 3:07 | 6:22 /mile |
| 3 | 1,200 m | 1:37 | 4:44 | 6:30 /mile |
| 4 | 1,600 m | 1:30 | 6:14 | 6:02 /mile |
| Average | 1,600 m | 1:33.5 | 6:14 | 6:16 /mile |
The laps show a runner who slowed through laps 2 and 3, then kicked hard at the end. The final split, 6:14, hides all of that. It's also not quite a mile: four laps make 1,600 m, a mile is 1,609.344 m, and the missing 9.3 m costs about 2 more seconds.
Pace is time per distance, so you scale the lap time up. For a 400 m lap:
A 1:32 lap is 92 seconds. 92 × 4.023 = 370 seconds, or 6:10 per mile. 92 × 2.5 = 230 seconds, or 3:50 per km. The table covers common lap times.
| 400 m lap time | Mile pace | Kilometer pace |
|---|---|---|
| 1:20 | 5:22 | 3:20 |
| 1:30 | 6:02 | 3:45 |
| 1:40 | 6:42 | 4:10 |
| 1:50 | 7:23 | 4:35 |
| 2:00 | 8:03 | 5:00 |
| 2:10 | 8:43 | 5:25 |
Paces are rounded to the nearest second.
The clock isn't the problem. Your thumb is. Simple reaction time to something you see is typically around 200 to 250 milliseconds, and it varies from press to press. You press late at the start and often early at the finish, and those errors don't cancel reliably.
Track and field takes this seriously. Under the rules, hand times are only counted to a tenth of a second, and any hundredths get rounded up to the next tenth, so 10.83 becomes 10.9. Statisticians who compare hand times against fully automatic timing commonly add 0.24 seconds to hand-timed 100 m and 200 m marks, because the timer at the finish is reacting to the starter's gun from a distance.
So treat a hand-timed reading as good to about a tenth or two, even though the display shows thousandths. Fine for a workout or a speech rehearsal, not for settling a close race.
One habit helps most: press when the same body part crosses the line every lap, such as the torso.
Start, lap, pause and resume with millisecond display. Nothing to install, nothing uploaded.
Open the Stopwatch →Yes. Browsers slow down timers on hidden pages. Chrome checks timers in a background tab about once a second, and after five minutes hidden it can stretch some to once a minute. A stopwatch that counted its own ticks would drift badly.
Ours doesn't count ticks. It refreshes the display every 10 ms while you're watching, but each refresh works out the elapsed time from the system clock (now minus the start time). When the tab is in the background the numbers just update less often. Switch back and the reading is correct.
Timesheets and invoices usually want hours as a decimal, not hours and minutes. Divide the minutes by 60.
| Minutes | Math | Decimal hours |
|---|---|---|
| 6 | 6 ÷ 60 | 0.10 |
| 15 | 15 ÷ 60 | 0.25 |
| 20 | 20 ÷ 60 | 0.33 |
| 30 | 30 ÷ 60 | 0.50 |
| 45 | 45 ÷ 60 | 0.75 |
| 50 | 50 ÷ 60 | 0.83 |
A stopwatch reading of 07:42:00 is 7 + 42/60 = 7.7 hours. Don't write it as 7.42, which is a common mistake and short-changes you by 17 minutes. Many firms bill in 6-minute blocks because each is a clean 0.1 hour. If you're adding up a whole week of start and end times, the hours calculator does the sums and the conversion together.
A stopwatch answers "how long did that take?" A countdown timer answers "tell me when time's up." If you know the length in advance, like a 3-minute plank, a 25-minute bake or a 60-second rest, use the countdown timer.
For focused work sessions, the Pomodoro timer runs 25-minute work blocks with short breaks built in. Use the stopwatch when the finish is open-ended.
Laps are segments, splits are running totals, and you can turn one into the other with simple addition. Use laps to check pacing, splits to check against a target, and trust hand timing to about a tenth of a second.
A lap time is how long one segment took, measured from the previous lap press. A split time is the total elapsed time from the start to that point. If your laps are 1:32 and 1:35, your splits are 1:32 and 3:07.
It shows lap times. Each press of Lap records the time since the previous lap, with the newest lap on top. To get a split, add up the laps so far, or read the main display at the moment you press Lap.
The clock itself is accurate to the millisecond. The weak link is your thumb. Simple visual reaction time runs around 200 to 250 ms, so a hand-timed reading can be off by a couple of tenths, which is why track rules round hand times up to the next 0.1 second.
Yes. Our stopwatch works out elapsed time from the system clock rather than counting ticks, so the reading stays correct. Browsers slow down timers in background tabs, so the display may refresh less often until you switch back.
Divide the minutes by 60. 15 minutes is 0.25 hours, 30 minutes is 0.5 and 45 minutes is 0.75. So 7 hours 42 minutes becomes 7 + 42/60 = 7.7 hours on a timesheet.