Running pace: time per unit of distance
Running pace is time divided by distance, usually shown as minutes per mile or minutes per kilometer. Speed is the reverse relationship: distance divided by time. Be consistent with the distance unit you select, because pace per kilometer and pace per mile are different.
Formula and example
pace = total time ÷ distance. A 10 km run completed in 50 minutes has an average pace of 50 ÷ 10 = 5 minutes per kilometer, or 5:00/km. A finish-time estimate can be found by multiplying the pace by the planned distance, assuming that same average pace is maintained.
Pace changes with terrain, weather, hills, rest stops, and how the distance and time were measured. Treat a calculated finish time as an arithmetic estimate, not a promise of performance. For comparison, make sure race and training distances use the same unit and that times include the same start and finish conventions.
Tips for accurate results
Pace is time divided by distance. Useful reference distances are 5K (3.107 miles), 10K (6.214 miles), a half marathon (13.109 miles), and a marathon (26.219 miles). A 25-minute 5K works out to about 8:03 per mile or 5:00 per kilometer.
Common mistakes and limits
GPS watches can be off by a small margin, and hills, wind, and heat change your effort at the same pace. Even pacing usually beats starting too fast. Make sure you are not mixing minutes per mile with minutes per kilometer when comparing results.