Running Pace Calculator
Calculate your race pace, finish time, per-km splits, and training zone paces.
How pace is calculated
Pace per km is your total race time divided by the distance in km — or, in reverse, your target pace multiplied by the distance gives a projected finish time. Training zone paces scale off race pace: easy runs at roughly 72% of race pace, long aerobic runs at 82%, tempo/threshold runs at 90%, and interval work at 100% (race pace itself).
Track your calorie burn during training with the Calorie Burn Calculator. For long-term fitness goals, see the Diet Outcome Estimator.
Frequently asked questions
- How is pace calculated?
- Pace per km is your goal finish time divided by the race distance in km (or, in reverse, your target pace multiplied by the distance gives your projected finish time). Pace per mile is derived by multiplying pace per km by 1.60934.
- What are training zones?
- Training zones are paces slower than race pace used for different types of runs: easy (~72% of race pace, for recovery), aerobic (~82%, for long runs), threshold (~90%, for tempo runs), and interval (100%, race pace itself, for VO₂max work).
- What pace do I need for a sub-4hr marathon?
- A 3:59:59 marathon requires roughly 5:41/km (9:09/mile) — use the "Sub-4hr Marathon" preset above to see the exact splits and training paces for this goal.
- How do I convert pace from km to miles?
- Multiply your pace per km (in seconds) by 1.60934 to get pace per mile. Switch the units selector above to see both instantly.
- Can I use this for other distances?
- Yes — select "Custom" as the race distance and enter any distance in km.
- Can I use this in my own app?
- Yes — every calculator on Stupidly Clever has a matching REST API and MCP tool that runs the same underlying logic.