Inputs
Use non-negative whole numbers for hours, minutes and seconds. Values of 60 or more are converted to total time.
The calculator has not loaded. Enable JavaScript to calculate. The values shown are a sample.
Sample result: 10 km at 5:00/km takes 50 minutes.
Seconds are rounded; speeds and distances show 2 decimals.
Splits (cumulative elapsed time)
Cumulative elapsed times at a steady pace without stops. Finish distances retain up to four decimal places.
| Distance | Elapsed time |
|---|---|
| 1.00 km | 00:05:00 |
| 2.00 km | 00:10:00 |
| 3.00 km | 00:15:00 |
| 4.00 km | 00:20:00 |
| 5.00 km | 00:25:00 |
| 6.00 km | 00:30:00 |
| 7.00 km | 00:35:00 |
| 8.00 km | 00:40:00 |
| 9.00 km | 00:45:00 |
| 10.00 km · Finish | 00:50:00 |
Up to 50 rows are shown: the first 49 checkpoints and the finish. Some intermediate checkpoints are omitted.
How to use (3 steps)
- Choose what to solve: distance, time, or pace/speed. Pick a race preset to fill distance when applicable.
- Enter the other two values with their units. Use hh:mm:ss for time and min/km or min/mile for pace.
- Press Calculate or edit an input to refresh speeds and lap splits. Copy results or a share URL when you’re happy.
Seconds are rounded; pace and speed are shown in both km and mile terms.
What these results mean
Estimates assume a steady pace with no stops. Lap tables use the calculated pace and round to whole seconds.
Use the share URL to keep your exact inputs. Adjust lap spacing to see key split times for your race plan.
How it’s calculated
- pace = time ÷ distance, speed = distance ÷ time, and distance = speed × time.
- Time is converted to seconds and distance to kilometers internally; miles use 1 mile = 1.609344 km.
- min/mile ↔ min/km pace is converted via the same factor. Speed is shown in km/h and mph.
- Seconds are rounded to the nearest whole second before showing hh:mm:ss or pace; speeds and distances show 2 decimals.
FAQ
Should I enter pace as min/km or min/mile?
Use min/km for most international races and min/mile if you think in miles. The calculator converts both ways and also shows km/h and mph.
How are pace and speed converted?
Pace is kept in seconds per kilometer internally. min/mile is converted using 1 mile = 1.609344 km. Speed is distance divided by time, then shown in km/h and mph rounded to 2 decimals.
How do I plan a sub-4 marathon or other targets?
Select Pace / Speed, choose a distance or race preset, and enter your target finish time. For a finish under four hours, try 3:59:00. Pace is rounded to whole seconds; use the entered total time and the finish row to check an exact target.
Is anything stored or sent to a server?
Calculations run in this page. Copy URL copies a link containing your inputs to the clipboard. Anyone who opens the link can see those inputs, so share it only where appropriate.
What input should I start with?
Pick any two of distance, time, and pace to solve the third. If you have a race target, start by choosing the preset distance, then enter your goal time or pace.