How this calculator works
The split distance divides the run into equal checkpoints. The number of full splits is the run distance divided by the split distance, rounded down. Multiplying the number of splits by the split distance gives the distance covered by the full splits; anything left over is the final partial split. With a constant pace, every full split takes the same time, and the elapsed time at split n is n times the split time. The final partial split is shorter than the chosen distance, so it takes proportionally less time.
Formula
Pace (seconds per km) = total time in seconds / distance in km. Full splits = floor(distance / split distance). Split time = pace x split distance in km. Elapsed time at split n = n x split time. Final partial distance = distance - full splits x split distance. Final partial time = pace x final partial distance in km.
Worked example
A 10 km run at 5:00 per kilometre takes 3,000 seconds. With a 1 km split distance there are 10 full splits of 300 seconds each, and the elapsed time at 5 km is 1,500 seconds, or 25:00. Choosing a 3 km split distance gives 3 full splits of 900 seconds and a final partial split of 1 km, so the table shows 3 km at 15:00, 6 km at 30:00, 9 km at 45:00 and 10 km at 50:00.
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Frequently asked questions
What split distance should I use?
One kilometre or one mile is standard for road races, with 5 km segments common in marathon plans. For interval training, use the length of each repetition. A shorter split distance gives more checkpoints but more numbers to remember.
Why is the final split shorter?
Most race distances are not an exact multiple of the split distance. A marathon is 42.195 km, so at 5 km splits the last segment is 2.195 km. The table shows it separately rather than pretending it is a full split.
Does a constant pace mean even effort?
No. On a hilly course, holding a constant pace costs more effort uphill and less downhill. Even effort usually means a slower pace uphill and a faster one downhill, and it tends to produce a better finish time.
Can I use this for a bike ride or a swim?
The arithmetic is the same for any distance-based activity. Enter the distance in the units you prefer and the pace per kilometre, or the total time, and read the split times at your chosen interval.