How the pace is worked out
Pace is simply time divided by distance. Forty-five minutes over 10 km is 4:30 per kilometre; the same run is 7:14 per mile. The calculator does that division and also flips the result into speed, so you can compare a treadmill reading in km/h with a watch showing min/mile without converting anything by hand.
Using the split table
The table lists elapsed time at every kilometre or mile. Even pacing is the assumption, which makes it a target rather than a prediction. Most runners lose 20–40 seconds in the second half of a race, so a realistic plan runs the first half a little slower than the average shown here.
Check the splits against course markers rather than GPS. In a city race, tall buildings can add 200–400 m of phantom distance over a marathon.
Pace, speed and effort
Pace is not effort. Heat, hills and wind all change the cost of a given pace: roughly 2–3% per 5°C above 15°C, and 10–20 seconds per kilometre into a strong headwind. Use the pace as a starting point and let heart rate or feel adjust the rest.
Frequently Asked Questions
Why is my watch pace different from this?
GPS smoothing and auto-pause both change the number. A measured course and a stopwatch are more reliable than instant pace, especially under trees or between buildings.
Can I use this for walking or cycling?
Yes — the arithmetic is the same. For cycling, speed in km/h is the more common unit, and the minutes-per-kilometre tool converts between them.
What is a good pace?
That depends entirely on the distance and your fitness. Put a recent race into the race predictor to see what a realistic pace looks like for your next goal.
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Privacy & your data
SwimRunPace calculates everything in your browser. Distances, times and body weights are never uploaded — there is no account, no server-side record and no training history stored between visits.