Free Tool

Running Pace Calculator

Predict your finish time for any distance

Enter a recent race result and instantly see predicted finish times across every major distance.

Your recent race distance

Your finishing time

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Your predicted race times

Distance Predicted Time Pace / km Pace / mile

How it works

How to use this calculator

Enter the distance and finishing time from a recent race. The closer that race is to the distance you're predicting, the more accurate the result. A 10k result will predict a half marathon time more reliably than a parkrun will predict a marathon, simply because the physiological demands are more similar.

The predictions are based on Riegel's formula, one of the most widely used and tested models in distance running. It accounts for the fact that longer races require a slower pace, not a simple straight-line projection.

Benchmarks

What is a good running pace?

There is no single answer to this and that is the beauty of running. A good pace is one that represents progress for you. That said, here are some general benchmarks by distance:

5k

Sub 25 minutes

5:00/km or 8:03/mile, a solid target for recreational runners.

Sub 20 minutes

3:59/km or 6:25/mile, competitive club runner territory.

10k

Sub 50 minutes

5:00/km or 8:03/mile, a popular first goal.

Sub 40 minutes

4:00/km or 6:26/mile, typical of serious club runners.

Half Marathon

Sub 2 hours

5:41/km or 9:09/mile.

Sub 1:45

4:58/km or 8:00/mile, strong for committed amateur runners.

Marathon

Sub 4 hours

5:41/km or 9:09/mile, the most common goal for first-time marathoners.

Sub 3:30

4:58/km or 8:00/mile, widely regarded as running competitively.

Sub 3 hours

4:15/km or 6:50/mile, top few percent of all marathon runners.

Just for fun, when Sebastian Sawe set a world record of 1:59:30 at the 2026 TCS London Marathon he averaged roughly 2:50 per km or 4:33 per mile over 26.2 miles. He recorded a negative split, passing halfway in 1:00:29 and running the second half in an incredible 59:01.

FAQ

Frequently asked questions

How accurate are race time predictions? +
Reasonably accurate when you use a recent result from a similar distance. The formula assumes consistent fitness and pacing, so a well-executed 10k is a better input than a parkrun you ran with your dog. Predictions also assume you are adequately trained for the target distance, not just capable of completing it. Some runners will be more suited to shorter distances or vice versa.
How do I calculate my running pace? +
Divide your finish time in seconds by the distance in kilometres or miles. For example, a 50-minute 10k is 50 x 60 = 3,000 seconds divided by 10km = 300 seconds per kilometre, which is 5:00/km.
What pace do I need to run a sub-3 hour marathon? +
You need to average 4:15/km or 6:50/mile for the full 42.2km. That is 2 hours 59 minutes and 59 seconds of sustained effort.
What pace do I need to run a sub-3:30 marathon? +
You need to average 4:58/km or 8:00/mile.
What pace do I need to run a sub-4 hour marathon? +
You need to average 5:41/km or 9:09/mile.
What pace do I need to run a sub-2 hour half marathon? +
You need to average 5:41/km or 9:09/mile.
What pace do I need to run a sub-1:45 half marathon? +
You need to average 4:58/km or 8:00/mile.
What pace do I need to run a sub-1:30 half marathon? +
You need to average 4:15/km or 6:50/mile.
What pace do I need to run a sub-20 minute 5k? +
You need to average 3:59/km or 6:25/mile.
What pace do I need to run a sub-25 minute 5k? +
You need to average 5:00/km or 8:03/mile.
What pace do I need to run a sub-45 minute 10k? +
You need to average 4:30/km or 7:14/mile.
What pace do I need to run a sub-50 minute 10k? +
You need to average 5:00/km or 8:03/mile.
What is a negative split in running? +
Running a negative split means the second half of your race is faster than the first. It is widely regarded as the most effective race strategy for most distances. Starting slightly slower than goal pace means you conserve energy early and can push harder when it counts.
Should I run at the same pace throughout a race? +
Even pacing, or slight negative splitting, tends to produce the best results. Going out too fast is the most common race mistake at every level. Use this calculator to set a realistic goal pace, then build your race plan around it.
How do I improve my running pace? +
The most effective approach combines structured training with genuine recovery. You need a mix of easy aerobic running (the majority of your weekly volume), threshold work to raise your lactate threshold, and shorter faster intervals to develop speed. Consistency over months and years matters far more than any single session.

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