How to use the pace calculator
- Choose what to solve for: pace, finish time or distance.
- For pace or time, enter the distance and pick miles or kilometers. Use the race buttons for 5K, 10K, half marathon or marathon.
- Enter the time as hours, minutes and seconds, or enter the pace as minutes and seconds per mile or per kilometer.
- Read the pace per mile and per kilometer, the speed in mph and km/h, and the table of splits.
Formula
pace = time / distance
time = distance x pace
distance = time / pace
speed = distance / time, and 1 mile = 1.609344 km
Pace is time per unit of distance, so a smaller pace is faster. Speed is its inverse, distance per unit of time.
Worked examples
5 km in 25:00. 1,500 seconds / 5 km = 300 seconds, so the pace is 5:00 per km. In miles, 5 km is 3.1069 mi, and 1,500 / 3.1069 = 482.8 seconds, so 8:03 per mile. The speed is 12 km/h or 7.46 mph.
Marathon at 9:00 per mile. 26.2188 mi x 540 seconds = 14,158 seconds, which is 3:55:58.
Half marathon in 2:00:00. 7,200 seconds / 13.1094 mi = 549 seconds, so 9:09 per mile and 5:41 per km.
1 hour at 8:00 per mile. 3,600 / 480 = 7.5 miles, which is 12.0701 km.
Race distances
The presets use the official distances: a 5K is 5 km, a 10K is 10 km, a half marathon is 13.1094 miles (21.0975 km) and a marathon is 26.2188 miles (42.195 km). One mile is exactly 1.609344 km, so converting between a mile pace and a kilometer pace is the same ratio every time.
Splits at an even pace
The table lists your elapsed time at the end of every mile or kilometer, based on the unit you used for the distance, and adds a finish row for any partial distance. It assumes an even pace. Real races have hills and fatigue, so treat the splits as a plan and a target, and adjust for the course. For long distances the table shows the first 100 splits, and the CSV download holds the same rows.
Rounding and validation
Times are rounded to the nearest whole second for display. The inputs must make sense: distance, time and pace must all be greater than zero, minutes and seconds must be below 60, and distance is limited to 1,000. Use whole hours and minutes, and seconds may have decimals. For other conversions use the unit converter, for adding times use the time calculator, and for trip fuel costs see the fuel cost calculator.
Assumptions and limits
- Pace is constant for the whole distance, with no stops or slowdowns.
- Distance is entered in miles or kilometers, and the other unit is derived using 1 mile = 1.609344 km.
- Displayed times are rounded to the nearest second, half up.
- Distances up to 1,000 and times up to 999 hours are accepted.
- Nothing is stored or uploaded. Your numbers stay in your browser.
Frequently asked questions
How do I convert a mile pace to a kilometer pace?
Divide the seconds per mile by 1.609344. A pace of 8:00 per mile is 480 seconds, which is 298 seconds, or 4:58, per kilometer.
What pace do I need to run a marathon in under four hours?
Four hours is 14,400 seconds, and dividing by 26.2188 miles gives about 549 seconds, or 9:09 per mile. That is about 5:41 per kilometer.
Is pace the same as speed?
They describe the same motion in opposite ways. Pace is time per distance, like minutes per mile. Speed is distance per time, like miles per hour. A 10:00 per mile pace is 6 mph.
Why is the finish row not on a whole mile?
Races rarely end on a whole number. A 5K is 3.1069 miles, so after three full miles there is a last partial split to the finish line.
Can I solve for distance if I know my time and pace?
Yes. Choose distance, enter the time and the pace, and the tool divides one by the other and shows the result in both miles and kilometers.