Running pace calculator
Enter how far you ran and how long it took to see your pace per mile and per kilometre, your speed, and the finish times that pace produces at race distances.
Your pace per mile
9:12
5:43 per km, 6.53 mph
How to use it
- Enter the distance you ran and pick miles or kilometres. A 5K is 3.1 miles; a 10K is 6.2.
- Enter the time in hours, minutes and seconds.
- Read the pace per mile and per kilometre, and your average speed.
- Look at the race projections to see what the pace would give you at longer distances, remembering that pace usually slows as distance grows.
Worked example
A 3.1 mile run in 28:30.
1,710 seconds ÷ 3.1 miles = 551.6 seconds a mile, which is 9:12 per mile. Per kilometre: 1,710 ÷ 4.989 km = 342.8 seconds, 5:43 per km. Speed 6.53 mph.
Held for a 10K that pace gives 57:08, for a half marathon 2:00:32, and for a marathon 4:01:04.
How this is calculated
Pace is time divided by distance, and the calculator converts between miles and kilometres using the exact factor of 1.609344 kilometres to the mile. The total time in seconds divided by the miles gives seconds per mile, shown as minutes and seconds; divided by the kilometres it gives the pace per kilometre. Speed is the distance divided by the hours. The race projections simply multiply the pace per kilometre by the official race distances: 5 km, 10 km, 21.0975 km for the half and 42.195 km for the full marathon. They're the times you'd run if you held exactly this pace, which is a useful reference and an optimistic one for anything much longer than the run you entered.
seconds per mile = total seconds ÷ miles
seconds per kilometre = total seconds ÷ kilometres, with 1 mile = 1.609344 km
speed = distance ÷ hours
race time = seconds per kilometre × race distance in km (5, 10, 21.0975, 42.195)
Rates, sources and limits
Arithmetic on the distance and time you enter. Race projections assume the same pace over a longer distance, which real runs rarely hold. Not medical or coaching advice.
Last reviewed 23 Sep 2026 by the CalcRabbit team. Estimates only, not financial, tax or medical advice.
Frequently asked questions
How do I use this to plan a race?
Enter the race distance and the finish time you want, and read the pace you'd need to hold. Then run your training at that pace to see whether it's realistic. Most runners can hold their 5K pace for about 20 to 30 minutes; a half-marathon pace is typically 20 to 40 seconds a mile slower than 5K pace, and marathon pace slower still.
Why are the race projections optimistic?
Because pace slows with distance. A common rule (Riegel's formula) adds about 6% to the pace each time the distance doubles, so a 28:30 5K predicts closer to 59:30 for a 10K than the 57:08 you'd get by holding the pace exactly. The projections here are the straight-line version; treat them as a ceiling.
What's the difference between pace and speed?
Pace is time per unit of distance, minutes per mile, and is what runners use because it maps directly to splits. Speed is distance per unit of time, miles per hour, and is what treadmills show. The calculator gives both; 6.0 mph is a 10:00 mile.
Does the calculator handle walking or cycling?
Yes, it's just arithmetic. A 20-minute mile walking or a 3-minute mile cycling work the same way. The race projections are only meaningful for running.