Running Pace Calculator
Solve pace, time or distance, get splits and a race-time predictor for any distance.
Enter a distance, then solve for pace or time.
Splits
Race-time predictor (Riegel's formula)
Predicted finish times at other distances, based on your current pace and effort.
Treadmill: pace ↔ speed
How pace, time and distance are calculated
Running pace links three numbers together: distance, time and pace (time per unit of distance). Knowing any two gives you the third:
pace = time ÷ distance time = pace × distance distance = time ÷ pace
Worked example: a 5K finished in 25:00 gives a pace of 25:00 ÷ 5 = 5:00 per km. Converting to miles: 1 mile = 1.609344 km, so pace per mile = 5:00 × 1.609344 = 8:03 per mile. The same run's 10K-equivalent effort, using Riegel's formula T2 = T1 × (D2/D1)^1.06, predicts a 10K time of about 52:07 — slightly more than double the 5K time, because pace naturally slows a little as distance increases.
Splits and pacing strategy
The splits table above shows the cumulative time at each kilometre or mile if you hold the calculated pace evenly. Even, or slightly negative (second half faster than the first), splits are widely considered the most efficient way to race — starting too fast burns glycogen early and costs more time late in the run than it gains early on.
Treadmill pace conversion
Treadmills display speed, not pace, so the two need converting: pace in minutes per km = 60 ÷ speed in km/h, and pace per mile = 60 ÷ speed in mph. For example, 12 km/h = 60 ÷ 12 = 5:00 per km, which is the same effort as running a 5:00/km outdoor pace. 1 km/h ≈ 0.621371 mph, so 12 km/h ≈ 7.46 mph.
Practical tip: when comparing training paces across watches, treadmills and race results, always convert to the same unit first (per km or per mile) — mixing units is the most common source of pacing mistakes.
Running Pace Calculator: frequently asked questions
How do I calculate my running pace?
Divide your total time by your distance. A 5K (3.1 mi) run finished in 25:00 is 25:00 ÷ 5 = 5:00 per km, or 25:00 ÷ 3.1 = 8:03 per mile.
How accurate is the race-time predictor?
It uses Riegel's formula, T2 = T1 × (D2/D1)^1.06, which is a well-tested estimate for similarly-trained effort across distances. It gets less accurate the further apart the two distances are (e.g. predicting a marathon from a 5K assumes you have the endurance base to hold that effort for 4+ hours).
What is a good pace for a beginner runner?
There is no universal "good" pace — it depends on age, fitness and goals. Many new runners fall somewhere between 6:00 and 8:30 per km (roughly 9:40–13:40 per mile) for easy runs. Consistency matters far more than pace when starting out.
How do I convert treadmill speed to pace?
Pace per km (minutes) = 60 ÷ speed in km/h. Pace per mile = 60 ÷ speed in mph. For example 10 km/h on a treadmill is 60 ÷ 10 = 6:00 per km.
Why does my pace per mile look slower than my pace per km?
A mile (1.60934 km) is longer than a kilometer, so it takes proportionally longer to cover — the same running speed always gives a larger number of minutes per mile than per km.