How to Calculate Your Running Pace

Pace vs speed

Speed is distance over time (km per hour); pace is its inverse, time over distance (minutes per km). Runners prefer pace because it is what you feel and what a watch shows: "5:00 per km" is immediately meaningful in a way "12 km/h" is not.

Working out your pace

Pace = total time / distance. Run 10 km in 50 minutes and your pace is 50 / 10 = 5:00 per km. Run 5 miles in 40 minutes and it is 40 / 5 = 8:00 per mile. The Pace Calculator converts between time, distance and pace so you can fix any two and solve the third.

Converting km and miles

One mile is about 1.609 km, so a per-mile pace is always a larger number than the per-km pace for the same speed. To convert a per-km pace to per-mile, multiply by 1.609; a 5:00/km pace is about 8:03/mile. Getting this backwards is a common source of confusion in training plans.

Predicting a race time

Multiply your target pace by the race distance for a rough finish time: a 5:30/km pace over a 21.1 km half-marathon is about 1 hour 56 minutes. Real races drift a little slower over long distances as fatigue builds, so treat the estimate as a best case and pace the early kilometres conservatively.

Frequently asked questions

Should I train at race pace? Mostly no — most training is done easier than race pace, with shorter faster sessions mixed in. Running everything hard is how injuries start.

Why is my pace slower on hills? Because pace measures time per distance, not effort — climbing costs more energy for the same distance, so the number rises even when you are working harder.

How do I negative-split? Run the second half slightly faster than the first — it is the most reliable way to a strong finish.