Calculate running pace, finish time, or distance — enter any two, get the third. Plus speed in mph & km/h and splits for common race distances.
Fill any two — pace, time, or distance — to solve the third.
Your pace
Pace / km
4:58/km
Total time
40:00
Speed
7.5 mph
Speed (km/h)
12.1 km/h
| Race | Distance | Predicted time | At your pace |
|---|
The Formula
Pace, time, and distance are linked by a single equation: pace = time ÷ distance. Give us any two, and we solve for the third — then convert to per-km pace, mph, and km/h.
For race predictions, we apply your pace to standard distances (5K, 10K, half, full marathon). These assume constant speed — in reality you'll usually slow slightly over longer races.
Pace Math
About This Tool
A pace calculator is the runner's swiss-army knife. Given any two of distance, time, or pace, it solves the third — and gives you speed in mph and km/h plus splits for every common race distance.
Use it to plan a target race time (enter goal pace + race distance), check tempo-run pace (enter time + distance), or work backwards from a finish time you want at a 10K (enter target time + 10K distance to see required pace).
All maths assumes constant pace. Real-world running involves hills, wind, fatigue, and pacing strategy — your actual race time will land within a few percent of the prediction if you've trained for the distance and paced sensibly.
Live Results
Pace, time, distance, and speed update instantly.
Solves Any Variable
Enter any two — pace, time, distance — to get the third.
Race Splits
5K, 10K, half marathon, marathon — predicted times.
100% Free & Private
No account needed. All maths runs in your browser.
Per-Mile & Per-KM
Both pace units shown side-by-side.
Imperial & Metric
Switch between miles, km, and metres freely.
Three fields, infinite running plans.
Choose km, miles, or metres. The label updates to match.
5K is 3.1 mi or 5 km. Marathon is 26.2 mi or 42.2 km.
Fill one to solve for the other. Leave a field blank to flag it as the unknown.
The big number is your pace per mile. Per-km and speed (mph/kph) are in the stat row.
The schedule tab predicts your time at 5K, 10K, half, and full marathon — useful for goal-setting.
Plug in a goal time, see required pace, then train at the prescribed pace for 8–12 weeks.
Everything you need to know about pace, time, and race planning.
Pace = total time ÷ distance. Running 5 miles in 40 minutes gives 8 minutes per mile. This calculator does the conversion automatically — including per-km, mph, and km/h.
It depends on goal and experience. Recreational runners often target 9–11 min/mile on easy days. Sub-elite runners aim for 6–7 min/mile race pace. The best comparison is to your own past times.
The maths is exact assuming constant speed. Real-world pace varies with terrain, weather, fatigue, and strategy — actual race times can differ by 1–3% in good conditions and 5–10% in bad ones.
Speed in mph = 3600 ÷ pace in seconds per mile. So a 10-min/mile pace (600 seconds) is 6 mph. The calculator shows both speeds automatically.
Pace is time per unit distance (8:00/mi). Speed is distance per unit time (7.5 mph). Same information, inverted. Runners prefer pace because it maps directly to splits and watches; cyclists prefer speed.
Enter the race distance and your target time — the calculator shows the required pace. Train at that pace (or slightly faster) for at least 6–12 weeks before race day. Easy runs should be slower.
Almost. Treadmills don't account for wind resistance, so a 1% incline roughly matches the energy cost of outdoor running at the same pace. Display speeds can also vary 5–10% between machines.