Free online calculator
Running pace calculator
Calculate pace, time, or distance.
Running pace calculator
Enter any two of distance, time, or pace to calculate the third.
How to use this calculator
- 1
Enter two values
Fill in any two of the three fields: distance, total time, and pace. Leave the third blank to calculate it.
- 2
Use a distance preset
Click 5K, 10K, Half, or Marathon to fill the distance field instantly.
- 3
Read the result
The missing field is calculated automatically. Treadmill speed in km/h and mph appears in the results panel.
- 4
Clear and recalculate
Change any field and the results update immediately.
Formula
Pace (sec/km): time (sec) ÷ distance (km)
Time (sec): distance (km) × pace (sec/km)
Distance (km): time (sec) ÷ pace (sec/km)
Speed (km/h): distance ÷ time × 3 600
Pace per mile: pace per km × 1.609 344
Worked example
10 km in 50:00:
Pace = 3 000 ÷ 10 = 300 sec/km = 5:00/km. Pace/mi = 300 × 1.609 = 483 sec ≈ 8:03/mi. Speed = 10 ÷ 3000 × 3600 = 12.0 km/h.
FAQ
How do I convert pace to speed? +
Speed (km/h) = 3600 ÷ pace (seconds per km). For example, a 5:00/km pace equals 3600 ÷ 300 = 12 km/h. This calculator shows both automatically.
What's a good marathon pace? +
A sub-4-hour marathon requires a pace of about 5:41/km (9:09/mi). Elite runners finish in under 2:10, which is around 3:05/km. Most recreational runners target 4:30–5:30/km.
Does treadmill speed match outdoor pace? +
Treadmill speed is mechanically consistent, but outdoor running on varied terrain, wind, and gradient changes the actual effort. At 0% incline, treadmill speed and outdoor pace are approximately equivalent on flat ground.
What format should I enter for time? +
Enter time as mm:ss or h:mm:ss. For example, 25:30 for 25 minutes and 30 seconds, or 1:45:00 for 1 hour 45 minutes. Pace uses mm:ss per km or mi.
What is the half-marathon distance? +
A half-marathon is exactly 21.0975 km (13.1094 miles). A full marathon is 42.195 km (26.2188 miles). These exact values are used in the presets.
About this calculator
This running pace calculator solves the triangle of distance, time, and pace — enter any two and it computes the third. It also shows treadmill speed in km/h and mph, making it useful for planning race targets, setting treadmill intervals, or reviewing a completed run.
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