Calculate Pace
Enter your distance and finish time. Pace = Time ÷ Distance. Example: 50:00 for 10 km = 5:00 min/km.
Running Pace & Race Time Predictor
Fast Online Running Pace Calculator
100% Free, Browser-Based Running Pace, Time & Distance Calculator.
Running pace, time and distance calculator
Your Pace
/km
10 km in 50:00
Pace / km
5:00
Pace / mile
8:03
Speed
12.00 km/h
Speed
7.46 mph
Distance
10.00 km
6.21 mi
Total Time
50:00
3,000 seconds
Split Times per km
| Split | Lap Time | Cumulative |
|---|
Estimated Race Finishing Times
Even pace = same pace held for the whole race. Riegel = fatigue-adjusted prediction (T₂ = T₁ × (D₂/D₁)1.06).
| Race | Even Pace | Riegel |
|---|
How the Running Pace Calculator Works
Calculate Time
Enter target pace and race distance. Time = Pace × Distance. Example: 5:41/km × 42.195 km ≈ 3:59:50.
Calculate Distance
Enter run time and pace. Distance = Time ÷ Pace. Example: 1 hour at 6:00/km = 10 km.
Popular Race Goal Paces
| Goal | Pace / km | Pace / mile | Speed |
|---|---|---|---|
| Sub-20 min 5K | 4:00 | 6:26 | 15.0 km/h |
| Sub-25 min 5K | 5:00 | 8:03 | 12.0 km/h |
| Sub-50 min 10K | 5:00 | 8:03 | 12.0 km/h |
| Sub-2 hour Half Marathon | 5:41 | 9:09 | 10.5 km/h |
| Sub-3 hour Marathon | 4:15 | 6:51 | 14.1 km/h |
| Sub-4 hour Marathon | 5:41 | 9:09 | 10.5 km/h |
| Sub-5 hour Marathon | 7:06 | 11:26 | 8.4 km/h |
Why Use PaceCalculator?
- ✓Instant results — every keystroke recalculates pace, time, speed and splits with zero page reloads.
- ✓100% private — all math runs locally in your browser; nothing is uploaded or stored on a server.
- ✓Metric & imperial — switch between km/min per km and miles/min per mile at any time.
- ✓Race-ready planning — copy split tables for pace bands and predict 5K to 50K finish times.
Frequently Asked Questions
How to calculate running pace per km or mile?
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Divide your total running time by the distance covered. For example, 50 minutes over 10 km is 50 ÷ 10 = 5:00 per km. For pace per mile, divide by the distance in miles instead (10 km = 6.214 mi), giving 8:03 per mile. Use the Calculate Pace tab above to do this instantly.
What pace is needed to run a sub-4 hour marathon?
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A marathon is 42.195 km (26.2 miles). To finish under 4:00:00 you must average faster than 5:41 per km or 9:09 per mile. Many runners aim for about 5:35/km (9:00/mi) to leave a buffer for aid stations, crowded starts and late-race fatigue.
How to use split tables for race pacing?
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A split table shows the cumulative time you should see on your watch at every kilometer or mile marker. Compare your actual time at each marker with the table: if you are ahead, ease off slightly to save energy; if you are behind, close the gap gradually rather than surging. Click Copy Split Table to paste it into notes, print a pace band, or plan interval workouts.
How do I convert running pace to speed?
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Speed = 60 ÷ pace (in minutes). A 5:00 min/km pace equals 12 km/h; an 8:00 min/mile pace equals 7.5 mph. PaceCalculator works as a running speed converter, showing pace and speed in both metric and imperial units automatically — handy for treadmill settings.
How accurate are the race time predictions?
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The Even Pace column multiplies your pace by each race distance. The Riegel column uses Pete Riegel's formula T₂ = T₁ × (D₂ / D₁)1.06, which accounts for slowing down over longer distances. Predictions are most reliable between nearby distances and assume you have trained appropriately for the longer race.
Is PaceCalculator free and private?
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Yes. PaceCalculator is completely free, needs no sign-up, and runs 100% in your browser. Your times and distances never leave your device.