# Pace Calculator

> Enter any two of distance, time and pace to work out the third, in minutes per km or per mile, with speed and finish times for common race distances.

Category: Health & fitness · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/pace-calculator

Pace is time divided by distance. Give any two of distance, finish time and pace, leave the third blank, and the calculator solves for it.

Also called: Running pace calculator, Race time calculator.

## Inputs
- Distance (options: Enter distance, 5 km, 10 km, Half marathon (21.0975 km), Marathon (42.195 km); default custom)
- Custom distance (default 10; optional)
- Distance in (options: Kilometres, Miles; default km)
- Time: hours (unit h; default 0; optional)
- Minutes (unit min; default 50; optional)
- Seconds (unit s; default 0; optional)
- Pace: minutes (unit min; default ; optional)
- Pace: seconds (unit s; default ; optional)
- Pace per (options: Kilometre, Mile; default km)

## Results
- Result
- Pace per km
- Pace per mile
- Time (h:mm:ss)
- Speed
- Speed
- Distance
- Distance

## Formula

```
Pace = Time ÷ Distance;  Time = Pace × Distance;  Distance = Time ÷ Pace;  Speed (km/h) = 60 ÷ pace (min/km)
```

Where:
- 1 mile: 1.609344 km (exact)
- half marathon: 21.0975 km
- marathon: 42.195 km

## Worked example
1. 50 minutes = 3,000 seconds; 3,000 ÷ 10 km = 300 s = 5:00 per km.
2. Per mile: 300 × 1.609344 = 482.8 s ≈ 8:03 per mile.
3. Speed = 60 ÷ 5 = 12 km/h = 12 ÷ 1.609344 = 7.46 mph.

**Result:** Running 10 km in 50 minutes is a pace of 5:00 per km (8:03 per mile), or 12 km/h.

## What the result means

The finish-time table assumes you can hold the same pace for longer distances, which few runners can. As a rough guide, expect your pace to slow as the distance increases, especially beyond the half marathon.

## Assumptions and limits
- Even pace throughout.
- Paces and times are rounded to the nearest second.
- Does not adjust for hills, heat, wind or fatigue.
- GPS distance can differ from the officially measured course, so watch pace and official pace may not match exactly.

## Questions

### What pace is a sub-4-hour marathon?

Just under 5:41 per km (9:09 per mile): 42.195 km at 5:41 per km takes 3:59:48.

### How do I convert pace per km to pace per mile?

Multiply the pace in seconds by 1.609344. For example, 5:00 per km is 300 s × 1.609344 = 483 s, or 8:03 per mile.

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Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/pace-calculator