Calculator
Pace calculator
Work out your running pace, finish time or distance, convert between min/km and km/h, and adjust your pace for the heat.
Pace, time and distance
h : m : s
Pace ↔ speed converter
Type a pace or a speed and the other values update instantly.
- km/h
- /mile
- mph
- /km
- /mile
- mph
Heat-adjusted pace
Heat and humidity slow you down. Enter your usual cool-weather pace, the temperature and the humidity — we will show the realistic, adjusted pace.
Adjusted pace
Cool, favourable conditions — no meaningful adjustment.
The model uses the widely-used adjustment table based on the sum of temperature and dew point. The effect is larger over longer races and for slower runners; acclimatisation reduces it.
Why pace is the key to running
Pace (minutes per kilometre) is the single most important number in running: it drives your goal time, the intensity of your sessions and your race strategy. Your finish time is simply pace multiplied by distance — a small change in pace adds up to many minutes over a long race.
In a race, even pacing is crucial: starting too fast almost always falls apart near the end. Train at your goal pace and learn how it feels — then on race day you will know when you are in the zone.
How does heat slow you down?
In the heat your body must also spend energy on cooling: heart rate rises, fatigue comes earlier, and the same effort yields a slower pace. Humid air hinders sweat evaporation, which is why dew point is a better measure than relative humidity alone. The effect typically starts to matter above ~10–13 °C and grows quickly as heat and humidity rise.
Frequently asked questions
How do I work out my goal time?
Choose "Time" mode, enter the distance and your planned pace — the calculator gives your expected finish time. It works both ways: pace to time, or time to distance.
How do I convert between min/km and km/h?
Use the pace ↔ speed converter: type either value and the other updates instantly. km/h = 60 divided by your min/km pace.
How much does heat slow you down?
In pleasant conditions (below ~10–13 °C), almost nothing. In heat and humidity your pace can drop by several percent; the calculator estimates the realistic slowdown from temperature and dew point.
Should I run even or progressive pace?
For most runners, even or slightly progressive (negative split) pacing is best. Starting too fast burns your reserves; plan your pace for the goal distance and stay disciplined early on.
The results are indicative estimates. The heat adjustment is a population average — individual heat tolerance, acclimatisation and the course significantly affect your actual pace.