How to calculate running pace (per mile and per km)

Running pace is how long it takes you to cover one mile or one kilometer. It is the number most runners train by, because it stays useful whether the run is 3 miles or 26.2.

There are only three quantities: time, distance and pace. Know any two and you can work out the third.

Pace = time ÷ distance

Time = pace × distance

Distance = time ÷ pace

The hard part is not the formula. It is the minutes and seconds.

Step by step: pace from a finish time

Say you ran a half marathon in 1:55:00. Here is the full calculation.

1. Turn the time into seconds. 1 hour = 3,600 s, 55 minutes = 3,300 s. Total: 6,900 seconds.
2. Use the exact distance. A half marathon is 21,097.5 meters, according to World Athletics. One mile is exactly 1,609.344 meters (NIST). So the race is 21,097.5 ÷ 1,609.344 = 13.1094 miles.
3. Divide. 6,900 ÷ 13.1094 = 526.3 seconds per mile.
4. Turn seconds back into minutes. 526 ÷ 60 = 8 minutes, with 46 seconds left over. Pace: 8:46 per mile.

Per kilometer, divide by 21.0975 instead: 6,900 ÷ 21.0975 = 327.1 s, or 5:27 per km.

The most common mistake is step 4. A pace of 8.77 minutes is not 8:77. The decimals are a fraction of a minute: 0.77 × 60 = 46 seconds.

Finish time from a pace

You want to know your marathon time at a steady 10:00 per mile.

1. 10:00 is 600 seconds.
2. A marathon is 42,195 m, or 26.2188 miles.
3. 600 × 26.2188 = 15,731 seconds.
4. 15,731 ÷ 3,600 = 4 hours, remainder 1,331 s. That is 22 minutes and 11 seconds.

Result: 4:22:11. The same pace gives a 2:11:06 half marathon.

Distance from time and pace

You have 45 minutes for a run and plan to hold 9:30 per mile.

1. 45 minutes = 2,700 s. 9:30 = 570 s.
2. 2,700 ÷ 570 = 4.74 miles, or about 7.6 km.

This is handy for planning a route before you leave the house.

Converting between min/mile and min/km

Because a mile is 1.609344 km, a pace per mile is always 1.609344 times a pace per km.

• Per km to per mile: multiply the seconds by 1.609344.
• Per mile to per km: divide the seconds by 1.609344.

Pace per mile	Pace per km	Speed
7:00	4:21	8.57 mph
8:00	4:58	7.50 mph
8:03	5:00	7.45 mph
9:00	5:36	6.67 mph
9:39	6:00	6.22 mph
10:00	6:13	6.00 mph
12:00	7:27	5.00 mph

All values come from the Pace Notes calculator and are rounded to the nearest second. Speed in mph is 60 divided by the pace in minutes: 60 ÷ 9 = 6.67 mph for a 9:00 mile.

Use the exact race distances

Race distances are fixed by the sport's governing body, not by habit.

Race	Meters	Miles
Mile	1,609.344	1.0000
5K	5,000	3.1069
10K	10,000	6.2137
Half marathon	21,097.5	13.1094
Marathon	42,195	26.2188

World Athletics lists the marathon as 26 miles 385 yards (42.195 km) and the half as 21.0975 km. If you divide by 26.2 instead of 26.2188, a 4:00:00 marathon comes out at 9:10 per mile instead of 9:09. That is a small error, but it adds up to about 10 seconds over the full race, and it makes your pace chart slightly too easy.

Why your watch disagrees

Certified courses are measured along the shortest path a runner can take, cutting every corner. You won't run that exact line, so your GPS watch usually shows a bit more than the official distance. Your average pace on the watch then looks a little faster than your real race pace. Plan on running a few seconds per mile quicker than your chart if you want to hit a goal time by the official clock.

Skip the arithmetic

The pace calculator solves for any one of pace, time or distance, in miles or kilometers, and shows the clock you should see at each checkpoint. For a full split table, use the split calculator. If you have a goal race in mind, start with the marathon pace chart or the 5K pace chart.