Running pace calculator
Convert between pace (min/km, min/mile) and speed (km/h, mph), estimate finish time for 5K, 10K, half marathon, and marathon distances, and derive easy/recovery/tempo/threshold paces from a recent race or goal pace.
How to calculate running pace
1. Enter a recent race time and distance, or target pace directly.
2. Switch units between min/km and min/mile as needed.
3. Read projected finish times for standard race distances.
4. Note suggested training zone paces (easy, tempo, interval) relative to goal.
Pace calculation examples
5K in 24:30
Average pace ≈ 4:54 min/km (7:52 min/mi). Projected 10K ≈ 51:00 at same effort (slower per km — doubling distance rarely doubles time).
Marathon goal 3:45:00
Required pace ≈ 5:19 min/km (8:34 min/mi). Easy runs ~6:15–6:45/km; tempo ~5:00–5:10/km — zones vary by coach method.
Treadmill 10 km/h
≈ 6:00 min/km pace (9:39 min/mi). Treadmill displays speed; outdoor watches show pace — convert when following treadmill workouts outdoors.
When to use this tool
• When you build a training plan from a recent parkrun or race result.
• When you follow a min/mile plan but your watch shows min/km.
• When you set realistic marathon pace from half marathon PR.
Pace vs effort on race day
Even pacing minimizes glycogen depletion in marathons. Heat, wind, and crowds add seconds per km — adjust goal. Heart rate drifts upward (cardiac drift) on long runs at constant pace; that is normal. Use recent races within 6–12 weeks for prediction; a 5K from three years ago overestimates current marathon fitness.
Frequently asked questions
How do I convert min/km to min/mile?
Multiply min/km by 1.609344 (or use this calculator). 5:00/km ≈ 8:03/mi.
What are training zones?
Easy/recovery: conversational. Tempo: comfortably hard ~20–40 min. Threshold: ~1-hour race effort. Intervals: faster, with rest.
Can I predict marathon from 5K?
Rough estimates yes; doubling distance needs endurance factor — marathon pace is slower than 2× 5K pace per km.
Race pace vs average pace?
GPS watches include stops; race clock is net time. Use official chip time for PR calculations.
Negative split strategy?
Run second half faster. Calculator gives even pace; plan 5–10 sec/km slower first half on hilly courses.