CALCSLIP

Running pace calculator

Pace, finish time or distance from the other two, with race times at that pace.

Work out

1:45:00 or 45:00

Race

Result

Pace per km
5:00
Pace per km
5:00
Pace per mile
8:03
Speed
12 km/h (7.46 mph)
Time
50:00
Distance
10 km (6.214 mi)
5K at this pace
25:00
10K at this pace
50:00
Half marathon at this pace
1:45:29
Marathon at this pace
3:30:59

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How this was calculated

  1. Pace

    Time ÷ distance

    50:00 ÷ 10 km = 5:00 /km

  2. Per mile

    Pace per km × 1.609344

    5:00 × 1.609344 = 8:03 /mi

  3. Speed

    3600 ÷ seconds per km

    3600 ÷ 300 = 12 km/h

What this calculation assumes

  • An even pace the whole way. Hills, heat, wind and crowded starts slow real races, and few runners hold a 5K pace over a marathon.
  • A half marathon is 21.0975 km and a marathon 42.195 km; a mile is exactly 1.609344 km.

In short

Pace is time ÷ distance and finish time is distance × pace. 10 km in 50:00 is 5:00 per km (8:03 per mile, 12 km/h), and holding that pace for a marathon (42.195 km) finishes in 3:30:59.

Pace, time and distance

Pace = time ÷ distance Time = distance × pace

Any two give the third. 10 km in 50:00 is a pace of 5:00 per km, which is 8:03 per mile and 12 km/h. Run a half marathon in 2:00:00 and the pace is 5:41 per km or 9:09 per mile.

The table under the result shows what the same pace means over 5K, 10K, a half marathon (21.0975 km) and a marathon (42.195 km): 5:00 per km is a 3:30:59 marathon.

Using it for race planning

Few runners keep their 10K pace over a marathon; a longer race is usually run several seconds per kilometer slower. Use a recent race to set a realistic pace, then work out the finish time, or start from a target time to find the pace to hold.

Questions people ask

How do I type a time?

As hours:minutes:seconds or minutes:seconds, for example 1:45:00 for a half marathon or 25:30 for a 5K. A pace of 5:30 means 5 minutes 30 seconds per km or mile.

What is a good pace for a beginner?

Comfortable is the right answer: a pace at which you can still talk, often 6:30 to 8:00 per km (10:30 to 13:00 per mile) for new runners.