Lap Time Calculator

Lap time in seconds is the track length in miles divided by the average speed in mph, multiplied by 3600. For example a 2.5 mile lap at 120 mph is 2.5 / 120 x 3600 = 75 seconds, shown as 1:15.000.

Yes. Switch to From a lap time and type the lap time in seconds, and the track length and speed are no longer needed. Add a lap count and it multiplies straight through to the total race time.

Not directly. The lap time field takes plain seconds, so a 1:15 lap is entered as 75. Multiply the minutes by 60 and add the seconds to get the value to type.

No. Choosing km only changes how the track length is read; the average speed field is always in mph. A kilometre length is converted to miles first (divided by 1.609344), then the same formula applies.

Lap time is minutes, seconds and thousandths, like 1:15.000, which keeps the fine precision drivers care about. Total race time is hours, minutes and whole seconds, like 1:02:30, and is rounded to the nearest second.

No. It assumes every lap is identical to the average you give, so it is a clean baseline rather than a full race prediction. To layer in stops and refuelling, pair it with a pit stop time calculator and a race fuel calculator.

No. Average speed is the mean across the whole lap, including corners, braking zones and slow sections, so it sits well below the top speed reached on the straights. Using a top speed here would give an unrealistically short lap.

Total race time is rounded to whole seconds for readability, so tiny per-lap fractions can add up to a second of difference over a long race. The per-lap figure keeps thousandths if you need the exact value.

Yes. The maths runs in your browser with nothing sent to a server, so it keeps working without a connection and none of your times or speeds leave your device.