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DayUtils

Pace Calculator – Running Pace, Finish Time and Race Predictor

Calculate your running pace per kilometre or per mile from a finish time, or work out your finish time from a target pace. You’ll also see your speed and predicted times for the 5K, 10K, half marathon and marathon.

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How to use the pace calculator

  1. Choose whether to work out your pace from a time or your finish time from a pace.
  2. Pick a distance — 5K, 10K, half marathon, marathon — or choose Other and enter your own.
  3. Choose kilometres or miles.
  4. Enter your finish time (such as 25:00) or your pace (such as 5:00).

You’ll see your pace per km and per mile, your speed in km/h and mph, and predicted times for the four classic race distances.

Pace formulas

Pace = Time ÷ Distance
Finish time = Pace × Distance
Speed = Distance ÷ Time

1 mile = 1.609344 km, so a pace per mile is the pace per km × 1.609.

Worked example

You run a 5K in 25:00:

  • Pace = 25:00 ÷ 5 = 5:00 per km (about 8:03 per mile)
  • Speed = 12 km/h (7.46 mph)
  • Predicted 10K = 52:07, half marathon = 1:55:00, marathon = 3:59:47

Race distances

RaceKilometresMiles
5K53.11
10K106.21
Half marathon21.097513.11
Marathon42.19526.22

Training with pace

  • Easy runs should feel conversational — often 60 to 90 seconds per km slower than your 5K race pace.
  • Tempo runs are “comfortably hard”, around your 10K to half-marathon pace.
  • Intervals are short, fast repeats close to or faster than 5K pace with recovery in between.
  • Race day: start slightly slower than goal pace and speed up if you feel good — starting too fast is the most common mistake.

Why your real pace may differ

Hills, wind, heat, humidity and crowded starts all slow you down. GPS watches can also measure distance slightly long or short, especially among tall buildings or trees. Use the calculator as a guide and adjust to the conditions on the day.

Pacing a race well

Even pacing — running each kilometre or mile at about the same speed — is usually the fastest way to cover a distance. Many experienced runners aim for a slight “negative split”, running the second half a little faster than the first. Write your target splits on your wrist or set them on your watch, and check them at each marker. If you fall behind early, don’t try to make it all up at once; gradually nudge the pace back towards your target.

For beginners, finishing comfortably is a better first goal than a fast time. Run your first race at a pace where you could still speak in short sentences, and use that result to set a realistic target next time. Use the race-prediction table as a guide for which distance to try next.

More training tools

Set training intensity with the heart rate zone calculator, fuel your training with the calorie calculator, and stay hydrated with the water intake calculator.

Frequently asked questions

How do I calculate running pace?

Divide your time by the distance. A 5K in 25 minutes is 25 ÷ 5 = 5 minutes per kilometre. Per mile it is 5:00 × 1.609 ≈ 8:03 per mile.

What pace do I need for a sub-4-hour marathon?

About 5:41 per kilometre or 9:09 per mile, held for all 42.195 km. Many runners aim a few seconds faster to allow for water stations and crowds.

How accurate are the race predictions?

They use Peter Riegel’s formula, T2 = T1 × (D2 ÷ D1)^1.06, which works well between about 5K and the marathon for trained runners. Predictions for longer races assume you’ve done the endurance training.

If I run a 25-minute 5K, what marathon time can I expect?

Riegel’s formula predicts about 52:07 for 10K, 1:55:00 for a half marathon and 3:59:47 for a marathon — if you train for the distance.

How do I type a time?

Use hours:minutes:seconds or minutes:seconds, such as 1:45:30 or 25:00. A single number is read as minutes.

What is a good running pace?

It depends on age, experience and distance. For new runners, an easy pace where you can still talk is the right place to start; most training should be at that pace.

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