CalcVitalsRunning Pace Calculator
Pace is time divided by distance. Run 5 km in 25:00 and your pace is 5:00 per kilometre (8:03 per mile) — hold it and you would finish a marathon in about 3:31. Enter any distance and time; this page returns the pace in both units and the classic finish times at that pace.
How it works
Pace is the runner's native unit: not how fast, but how long each kilometre takes. It inverts speed, and that inversion is what makes it useful — a pace target translates directly into the splits you check on your watch mid-run, and small pace differences compound into big finish-time differences (10 seconds per kilometre is worth over 7 minutes across a marathon).
This page does the unit work runners constantly need: per kilometre and per mile side by side, plus the speed equivalent for treadmill settings. The finish-time rows are simple linear projections — the same pace, held. They are honest arithmetic and deliberately naive physiology: fatigue makes long-distance pace decay, which is why the race predictor on this site uses Riegel's fatigue-aware formula instead of straight lines.
If you are working toward a goal time, run the calculation backwards in your head via the split planner: it takes a goal and a distance and returns even, negative or positive split plans, which is how a pace becomes a race strategy rather than a hope.
The method
Pace = total seconds ÷ distance. Per-mile pace = per-km pace × 1.609344. Speed = distance ÷ time. Projections multiply pace by 5, 10, 21.0975 and 42.195 km. Distances: half marathon 21.0975 km, marathon 42.195 km.
Frequently asked questions
What is a good 5K pace?
Highly individual. For orientation: many recreational runners finish 5K in 25–35 minutes (5:00–7:00/km); trained club runners go under 20 minutes (4:00/km); elite men run near 2:35/km. Your good pace is the one slightly faster than your last one.
Why is my treadmill pace different?
Treadmills remove wind resistance and the belt assists leg turnover slightly; a 1% incline is the traditional compensation. Belt calibration also drifts — a GPS-measured outdoor pace is the more trustworthy figure.
Should I train by pace or by heart rate?
Both have a place: pace for workouts with a target, heart rate (or plain effort) for easy days and hot weather, when the same pace costs more. The training pace zones calculator turns a recent race result into a full set of paces.