About the Pace Calculator
This Pace Calculator solves the three numbers behind every run: distance, time and pace. Choose what you want to find. Enter a distance and a time to get your pace, a distance and a pace to get your finish time, or a time and a pace to see how far you will run. Results show pace per kilometre and per mile, speed in km/h and mph, and a split table with your time at the end of every kilometre or mile. A Race predictions panel uses the Riegel formula to estimate other standard distances from your result. All figures assume an even pace, so real races with hills, heat or fatigue will differ, and predictions get less reliable above the half marathon. Your numbers stay on your device.
Updated September 2026
How to use the Pace Calculator
- 1Choose what to calculate: Pace, Finish time or Distance, and pick kilometres or miles.
- 2Type a distance, or tap a quick button such as 5K, half marathon or marathon.
- 3Enter your time as 50:00 or 1:45:30, or your pace as 5:00 per unit.
- 4Read the pace, speed and finish time, then check the splits and race predictions.
Pace, speed and time
Pace, time and distance are linked, so knowing any two gives you the third. Pace is time per unit of distance, so your finish time is pace multiplied by distance, and your distance is total time divided by pace. That is why the calculator has three modes: pick the one you are missing.
Enter times as hours, minutes and seconds separated by colons. Both 1:45:30 and 45:30 work, and a single number is read as seconds. Times up to 99 hours are accepted, and the result is rounded to whole seconds.
Splits for race day
The split table lists your clock time at the end of every kilometre or mile if you hold an even pace. Print or copy it, or write the key checkpoints on your wrist. If the distance is not a whole number, such as 21.0975 km, the last row shows the partial split with your finish time.
Even pacing is a plan, not a rule. Most people run the first miles a little faster than they should. Use the splits to notice when you are ahead of schedule and ease off before the hard part of the course.
Predicting other distances
Open Race predictions to see estimated times for the 5K, 10K, 15K, half marathon and marathon from your current result. The Riegel formula works best for distances that are not far apart, such as a 10K result predicting a half marathon.
- Predictions assume similar training for each distance.
- Accuracy falls above the half marathon and for beginners.
- Hills, weather and course length are not included.
Kilometres and miles
One mile is 1.609344 km, and every pace and speed here uses that exact number. Switch the Units setting and the quick distance buttons fill in the equivalent in miles, for example 26.2188 miles for the marathon. For other conversions, use our Unit Converter.
To time a run instead of calculating one, use the Stopwatch. To see how much energy a run uses, try the Calorie Calculator. To time your run live, start the Online Stopwatch, and convert miles to kilometres with the Unit Converter.
Features
- Pace, finish time or distance from the other two
- Kilometres or miles, with pace shown in both
- Speed in km/h and mph
- Split table for every km or mile plus a partial last split
- Quick buttons for 400 m, 5K, 10K, half marathon and marathon
- Race time predictions with the Riegel formula
- Copy the result in one tap
Frequently asked questions
How do I calculate running pace?
Divide your time by your distance. A 10 km run in 50 minutes is 3,000 seconds over 10 km, so 300 seconds per km, which is a pace of 5:00 per km. Enter the distance and time here and the calculator does it for you, in both kilometres and miles.
What pace do I need for a 4-hour marathon?
About 5:41 per km or 9:09 per mile. Pick Pace, choose the Marathon button and enter 4:00:00 to see it, along with the split for every kilometre. Many runners aim slightly faster early on to leave a cushion for the last miles.
How do I convert min/km to min/mile?
Multiply the pace by 1.609344, because a mile is that many kilometres. A pace of 5:00 per km is 300 seconds, times 1.609344 gives 482.8 seconds, which is 8:03 per mile. The calculator shows both paces for every result.
How accurate are race time predictions?
They are a rough guide. The Riegel formula multiplies your time by the distance ratio raised to the power 1.06, which assumes you train equally well for each distance. It tends to be optimistic for the marathon, especially for newer runners, so treat it as a target, not a promise.
What is a good 5K time?
It depends on age, fitness and experience. Many recreational runners finish a 5K in roughly 25 to 35 minutes, and beginners often take longer. A better goal than a fixed number is beating your own previous time.
What is the difference between pace and speed?
Pace is the time you take to cover one unit of distance, such as 5:00 per km. Speed is the distance covered in one unit of time, such as 12 km/h. They describe the same effort, and runners tend to use pace while cyclists use speed.