How to Calculate Running Pace
The exact formula for running pace, worked examples in km and miles, unit and speed conversions, and how to predict your pace at a new distance with Riegel's formula.
Quick answer: running pace is time divided by distance. Divide your finish time in seconds by the distance in km or miles to get seconds per km or per mile, then read that back as minutes and seconds.
The pace formula
Every pace calculation on this site, and every pace calculation a runner does by hand, comes from one relationship: pace = time / distance. The same equation rearranges to answer the other two questions runners ask most often. Finish time equals pace multiplied by distance, which tells you how long a given effort will take. Distance equals time divided by pace, which tells you how far a given effort will cover. All three forms are the same formula solved for a different variable, which is exactly what the pace calculator does when you give it any two values.
Worked example: pace from a race result
Say you ran a 5K in 25 minutes. First convert the time to seconds: 25 minutes is 1,500 seconds. Divide by the distance: 1,500 seconds / 5 km = 300 seconds per km. Convert that back to minutes and seconds: 300 seconds is 5:00, so your pace is 5:00 min/km. The same steps work for any distance and any unit, whether that is a 10K in 50 minutes (5:00 min/km again) or a half marathon in 1:45:00 (about 4:59 min/km over 21.0975 km).
Converting between min/km and min/mile
A mile is exactly 1.609344 km, so pace in min/km converts to min/mile by multiplying the pace in seconds by that factor. Continuing the example above, 5:00 min/km is 300 seconds; 300 x 1.609344 = 482.8 seconds, which rounds to 8:03 min/mile. Going the other way, divide a min/mile pace in seconds by 1.609344 to get seconds per km. This is the exact factor used throughout the site, not a rounded approximation like 1.6, so the numbers always agree with the treadmill pace converter and every pace chart.
Turning pace into speed
Treadmills and bike computers usually show speed rather than pace. To convert, use speed (kph) = 3600 / pace (seconds per km), since there are 3,600 seconds in an hour. A 5:00 min/km pace (300 seconds) gives 3600 / 300 = 12.0 kph. For mph, either apply the same formula to a min/mile pace or multiply the kph figure by 0.621371 (the inverse of 1.609344): 12.0 kph is about 7.5 mph. The full range of common paces and their speed equivalents is laid out in the pace conversion table.
Predicting your pace at a different distance
The formulas above convert a pace you already have. They cannot tell you what pace you could hold over a distance you have not raced, because effort does not scale in a straight line: doubling the distance costs more than double the time. The standard model for that slowdown is Riegel's formula, published by Peter Riegel in "Athletic Records and Human Endurance," American Scientist, vol. 69, no. 3 (1981), pp. 285-290. It reads t2 = t1 x (d2 / d1) ^ 1.06, where t1 and d1 are a known time and distance, d2 is the target distance, and 1.06 is the exponent Riegel found describes the fall-off in sustainable pace as endurance events get longer.
For example, a 20:00 5K (1,200 seconds) predicts a 10K time of 1,200 x (10 / 5) ^ 1.06 = about 41:42, not the naive 40:00 you would get by simply doubling. Stretched further, the same 20:00 5K predicts a marathon of roughly 3:11:49, reflecting how much more the model expects pace to fade over 42.195 km than over 10 km. The race time predictor runs this formula for any pair of distances so you do not have to work it out by hand.
Put it into practice
Use the pace calculator to solve for pace, time or distance from any two values, the finish time calculator to turn a target pace into a projected result, and the splits calculator to turn a goal time into a marker-by-marker plan. To see the pace behind a specific goal at a glance, check the pace chart for your distance, from the mile up to the marathon.
Frequently asked questions
What is the formula for running pace?
Pace equals time divided by distance: seconds divided by kilometres for min/km, or seconds divided by miles for min/mile. Rearranged, time equals pace multiplied by distance, and distance equals time divided by pace.
How do I calculate my pace from a race result?
Convert your finish time to seconds, then divide by the distance. A 25:00 5K is 1500 seconds divided by 5 km, which is 300 seconds per km, or 5:00 min/km.
How do I convert my pace between km and miles?
Multiply a min/km pace in seconds by 1.609344 to get seconds per mile, or divide a min/mile pace by that same number to get seconds per km. That factor is the exact number of kilometres in a mile.
How do I predict my pace for a different race distance?
Use Riegel's formula: new time equals known time multiplied by (new distance divided by known distance) raised to the power 1.06. It accounts for the natural slowdown as distance increases, rather than scaling time and distance in a straight line.