Divide your total time by the distance you ran to get your running pace per kilometre. A 5 km run finished in 28 minutes 30 seconds gives a pace of 5 minutes 42 seconds per kilometre.

The top-ranking pages are mostly calculators, and they leave three gaps. First, they rarely explain how to handle seconds in the division. Second, they seldom show a splits table, which is how runners actually use pace. Third, they rarely run the formula backwards, from a target pace to a finish time. This guide closes all three.

The formula is pace = time / distance, with time in minutes and distance in kilometres. Convert seconds to a decimal first: 30 seconds is 30 / 60 = 0.5 minutes, so 28 minutes 30 seconds is 28.5 minutes. Then divide: 28.5 / 5 = 5.7 minutes per kilometre. Convert the decimal back to seconds, 0.7 x 60 = 42 seconds, giving 5:42 per kilometre.

Worked example — a 10 km run. Finish 10 km in 52 minutes and the pace is 52 / 10 = 5.2 minutes per kilometre, which is 5:12 per kilometre. Pace also converts to speed: speed = 60 / pace in minutes, so 60 / 5.2 = 11.54 km/h. A lower pace number means a faster runner, while a higher speed number means the same thing, which is why beginners sometimes mix the two up.

Worked example — splits at 5:42 per kilometre. At 5.7 minutes per kilometre, 1 km takes 5:42, 5 km takes 5.7 x 5 = 28.5 minutes, and 10 km takes 5.7 x 10 = 57 minutes. A half marathon of 21.0975 km takes 5.7 x 21.0975 = 120.26 minutes, which is 2 hours and about 15 seconds. That is how a single pace number predicts every distance.

Worked example — running the formula backwards. To find the finish time for a target pace, multiply pace by distance. A target of 6:00 per kilometre over 10 km gives 6 x 10 = 60 minutes. A target of 5:30 per kilometre, which is 5.5 minutes, over a half marathon gives 5.5 x 21.0975 = 116.04 minutes, or about 1 hour 56 minutes.

Converting to miles. One mile is 1.609344 kilometres, so multiply a per-kilometre pace by 1.609344. A pace of 5.7 minutes per kilometre becomes 5.7 x 1.609344 = 9.17 minutes per mile, which is 9 minutes and about 10 seconds per mile. Use min/km if your watch and races are metric, and min/mile if they are imperial, but never mix the two in one calculation.

Bottom line: pace is time divided by distance, nothing more. Convert seconds to decimals before dividing, convert back to seconds for the answer, and the same number gives you splits, speed, and finish-time predictions.

Q: What is the formula for running pace?

A: Pace = time / distance. Divide your total time in minutes by the distance in kilometres to get minutes per kilometre.

Q: How do I handle seconds when calculating pace?

A: Convert seconds to a decimal first, 30 seconds = 0.5 minutes, then divide, then convert the decimal part back by multiplying by 60.

Q: How do I convert pace per kilometre to pace per mile?

A: Multiply by 1.609344, since one mile is 1.609344 kilometres. A 5:42 per kilometre pace is about 9:10 per mile.

Q: How do I predict my finish time from a target pace?

A: Multiply pace by distance. A 6:00 per kilometre pace over 10 km predicts 60 minutes, and a 5:30 pace over a half marathon predicts about 1 hour 56 minutes.