How to calculate running pace

Pace is simply your time divided by the distance. Here is the formula, how it relates to speed, how to convert between min/km and min/mile, and how to turn a pace into a race-time estimate.

By the Calculator Den team · Updated 2026-10-23

Running pace is the number almost every runner plans around: how long it takes you to cover one unit of distance, written as minutes and seconds per kilometre or per mile. It tells you whether a run was easy or hard, what to aim for on race day, and how to pace a long effort so you do not blow up halfway. The maths behind it is short, but a couple of conversions trip people up. A free running pace calculator handles them instantly, and the method below shows exactly what it is doing.

The running pace formula

Pace is just time divided by distance:

Pace = total time ÷ distance

Run 5 km in 25 minutes and your pace is 25 ÷ 5 = 5:00 per km. The only care needed is with the seconds: work in decimal minutes or in total seconds, then convert back. For example, 7 km in 38 minutes is 38 ÷ 7 = 5.43 minutes per km, and 0.43 of a minute is 0.43 × 60 = 26 seconds, so the pace is 5:26 per km, not 5:43.

Pace versus speed

Pace and speed describe the same run from opposite ends, and they are mathematical inverses. Pace is time per distance (minutes per km). Speed is distance per time (km per hour). To turn one into the other, divide 60 by the pace in minutes:

Speed in km/h = 60 ÷ pace in minutes per km

A 5:00 per km pace is 60 ÷ 5 = 12 km/h. The same works for miles: a pace of 8:00 per mile is 60 ÷ 8 = 7.5 mph. Runners almost always think in pace because it is the number you can hold in your head and chase on a watch, while treadmills and cycling tend to show speed. Neither is more correct; they are two views of the same thing.

Converting between min/km and min/mile

A mile is about 1.609 kilometres, so a mile takes longer to cover than a kilometre at the same effort, which means your per-mile pace number is bigger than your per-km number. To convert, multiply your per-km pace by 1.609 (and divide to go the other way):

A 5:00 per km pace is 5 × 1.609 = 8.05 minutes, and 0.05 of a minute is about 3 seconds, so roughly 8:03 per mile. Here is a quick reference:

Predicting a race time from your pace

Once you know a pace you can hold, you can estimate a finish time by multiplying it by the distance. At 5:00 per km, a marathon of 42.195 km would take 42.195 × 5 = 210.98 minutes, which is about 3 hours 31 minutes. That is a best case, though, because pace tends to fade over longer distances as fatigue sets in. A well-known rule of thumb from running coach Pete Riegel adjusts for this: your predicted time for a new distance is your known time multiplied by (new distance ÷ old distance) raised to the power 1.06, which gently slows the prediction the further you go. A worked example makes the fade concrete: a 25-minute 5 km predicts a marathon of 25 × (42.195 ÷ 5)^1.06 ≈ 240 minutes, about 4 hours, not the 3 hours 31 minutes you would get from holding 5:00 per km flat. That gap of nearly half an hour is the fade, and it is why a fast short-run pace will not survive a marathon. Treat the rule as a rough guide, most reliable for efforts of a few minutes up to a few hours and when your training matches the distance. In plain terms: hold something a little easier than your short-run pace when you race long.

Using pace in training

Pace is most useful when you deliberately run different sessions at different paces.

• Find your goal race pace, then practise holding it in shorter runs so it feels familiar on the day.
• Keep easy runs genuinely easy, well slower than race pace. If every run is fast, none of them is doing its job, and recovery suffers.
• Aim for even or negative splits, meaning you run the second half of a race at the same pace or slightly faster than the first. Starting too fast is the most common racing mistake, and pace is how you police it.
• Convert between units when you follow a plan written in the other one, so you always train at the right effort.

Common pace mistakes

• Treating the decimal as seconds. 5.43 minutes per km is 5:26, not 5:43. Multiply the decimal part by 60 to get the seconds.
• Mixing up pace and speed. A bigger pace number is slower; a bigger speed number is faster. They move in opposite directions.
• Using one unit's pace on the other. Running an 8:00 per mile plan at 8:00 per km is a big difference in effort, because a mile is longer than a kilometre.
• Expecting race pace to match short-run pace. Pace fades with distance, so your 5 km pace is not your marathon pace.

Divide time by distance, mind the seconds, and remember pace and speed are inverses, and the numbers stop being confusing. When you want it done at once, including the min/km to min/mile conversion and your speed, the free running pace calculator takes a distance and a time and shows your pace per km and per mile plus your speed, and the target heart rate calculator helps you pair pace with effort.