About the Pace Calculator
This pace calculator solves the three-way relationship between distance, time and pace. Enter any two and it finds the third: the pace you need for a goal finish time, the finish time a given pace produces, or how far you will get in a set time. Results are shown per mile and per kilometre, along with speed in mph and km/h.
Runners use it to set race-day goals, plan tempo and interval workouts, and check whether a target such as a sub-4 marathon or sub-25 5K is realistic. Walkers, hikers and triathletes can use it the same way. Pick a standard race distance or enter your own in miles or kilometres.
The splits table lists the elapsed time at each mile or kilometre marker for an even-paced effort, and the chart shows what the same pace would produce over other common race distances. Real races rarely run perfectly even — hills, heat and fatigue matter — so treat the numbers as targets and adjust on the day.
How to use the pace calculator
- 1Choose whether to calculate pace, finish time or distance.
- 2Select a race distance or enter a custom distance in miles or km.
- 3Enter your finish time and/or pace, depending on what you are solving for.
- 4Choose whether pace and splits are shown per mile or per kilometre.
- 5Read the result, then use the splits table as a race-day plan.
Formula and method
Pace is the time taken to cover one unit of distance, so it is simply total time divided by distance. The calculator converts everything to seconds and metres internally (1 mile = 1,609.344 m), then reports pace in minutes:seconds per mile and per kilometre, speed in mph and km/h, and elapsed times at each split.
Standard race distances use their official lengths: 5K = 5,000 m, 10K = 10,000 m, half marathon = 21,097.5 m and marathon = 42,195 m (26.219 miles). Splits assume an even pace; for negative splits run the first half slightly slower than the average and the second half slightly faster.
- Pace
- Time per mile or per kilometre (m:ss)
- Time
- Total elapsed time (h:mm:ss)
- Distance
- Distance covered in miles or kilometres
Worked examples
Pace for a 3:45 marathon
A marathon is 26.219 miles. 3:45:00 is 13,500 seconds, and 13,500 ÷ 26.219 = 514.9 seconds, or 8:35 per mile (5:20 per km). That is an average speed of about 6.99 mph.
Finish time for a 5K at 7:00 per mile
5 km is 3.107 miles. At 420 seconds per mile the run takes 420 × 3.107 = 1,304.9 seconds, a finish time of 21:45 at about 13.8 km/h.
Distance covered in 1 hour at 5:00 per km
An hour is 3,600 seconds; at 300 seconds per kilometre that covers 12 km, or 7.46 miles. The equivalent pace is 8:03 per mile.
Frequently asked questions
How do I calculate my running pace?+
Divide your total time by the distance. For example, 30 minutes for 5 km is 6:00 per km; converting to miles, 30 minutes ÷ 3.107 miles is a 9:39 per-mile pace.
What pace do I need for a sub-4-hour marathon?+
You need to average faster than 9:09 per mile, or 5:41 per kilometre. Many runners aim for about 9:00 per mile to leave a buffer for water stations and congestion.
What is a good 5K pace?+
It depends on age and experience. Many recreational runners finish a 5K in 25–35 minutes, which is 8:03–11:16 per mile. Use an age-grading calculator to compare times fairly across ages.
How do I convert pace per mile to pace per km?+
Divide the per-mile pace by 1.609. A 9:00 per mile pace (540 seconds) is 540 ÷ 1.609 = 335.5 seconds, about 5:36 per km.
How long is a marathon and half marathon?+
A marathon is 42.195 km (26.219 miles) and a half marathon is 21.0975 km (13.109 miles). These official distances are used for every standard race calculation here.