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Running pace calculator: pace, time and distance

Updated 29 October 2026 · 3 min read

Pace, time and distance are one equation: know any two and you have the third. Choose what you want to work out, enter the other two, and the calculator gives you the answer in kilometres or miles, plus the finish time for a 5K, 10K, half marathon and marathon at that pace.

Pace, time and distance in one line

• Pace = time ÷ distance
• Time = pace × distance
• Distance = time ÷ pace

The race distances use their official lengths: 5 km, 10 km, 21.0975 km for the half marathon and 42.195 km for the marathon. A mile is 1.609344 km. Your watch will often show a little more than the race distance at the finish, because nobody runs the measured line perfectly, so plan your target pace a few seconds per kilometre faster than the bare arithmetic says.

Turning a goal into a pace

Start from the finish time you want and choose Pace. The splits table shows what the same pace means at the other distances, which is a quick reality check: if your goal marathon pace would give a 10K time you have never run, the goal is ambitious. For a prediction based on what you have already run, use the race time predictor, which accounts for the fact that pace slows as races get longer.

Pace is not the same as effort

Hills, heat, wind and tired legs all change how hard a given pace feels. That is why easy runs are better steered by heart rate or feel than by pace, and why the same 5:30 per kilometre can be easy in October and hard in July. Keep pace targets for intervals, tempo runs and races, where hitting a number is the point, and use your heart rate zones for the rest.

Grade-adjusted pace helps on hilly routes: it estimates the flat pace that would have cost the same effort, so a slow climb no longer looks like a bad day. Keho shows it in the analysis of runs that carry elevation data.

Questions

How do I enter times?

Use colons: 25:00 is 25 minutes, 1:45:30 is one hour, 45 minutes and 30 seconds. A single number is read as minutes. Distances accept a decimal point or a comma.

Why does my watch show a different pace?

GPS measures your path, not the course, and it drifts under trees and between tall buildings. Watches also smooth the live pace, so the average at the end is the number to compare with this calculator.

What pace should my long runs be?

Most plans put long runs about 60–90 seconds per kilometre slower than goal race pace for a half marathon or marathon. Our half marathon and marathon guides explain how the paces fit together.