How do I calculate running pace?

Divide total time by distance. For a 25 minute 5K that is 25 divided by 5, which is 5 minutes per kilometre. This tool handles the conversions and the unit switching for you.

What pace is a 4 hour marathon?

About 5 minutes 41 seconds per kilometre, or 9 minutes 9 seconds per mile, held for the full 42.2 kilometres.

Should I train at race pace?

Mostly not. Most weekly volume should be comfortably slower, at conversational effort, with a smaller amount of faster work. Training at race pace constantly is a common route to being tired and injured.

Can I predict my marathon time from a 5K?

Not reliably. Prediction formulas assume endurance scales in a way that often does not hold for amateur runners, since the marathon is limited by fuelling and durability rather than speed. This tool deliberately does not guess.

Running pace calculator

Give it any two of pace, time, and distance, and it works out the third.

Runs in your browser. Nothing is sent, saved, or shared.

What are you solving for?

Distance

Target finish time

mm:ss or h:mm:ss, for example 1:45:00

Required pace

05:00 /km

08:03 per mile for 5.00 km

Per km: 05:00
Per mile: 08:03
Speed: 12.0 km/h

Split times at this pace
Split	Time
1 km	05:00
5 km	25:00

Three numbers, any two of them

Pace, time, and distance are locked together, so fixing two gives you the third. That is the whole tool. Enter a target finish time for a distance and it tells you the pace to hold; enter a pace and it tells you when you would finish.

The common use is checking whether a goal is realistic. Seeing that a sub four hour marathon means holding 5:41 per kilometre for the whole thing is more informative than the target on its own.

Race pace is not training pace

The pace this gives you for a race is close to your limit for that distance. Training mostly at that pace is how people arrive at races tired, and it is the most common self-inflicted injury in amateur running.

The usual guidance is that most weekly volume sits well below race pace, conversational, with a small share of harder work. It feels too slow. It is not.

Predicting across distances is unreliable

Formulas that turn a 5K time into a marathon prediction assume your endurance scales the way the model expects, and for most amateur runners it does not, because the marathon is limited by fuelling and durability rather than raw speed.

This tool converts between pace, time, and distance and stops there. It deliberately does not predict a marathon from a parkrun, because that number would be confidently wrong.

How to use a pace calculator

1
Pick a distance
Common race distances are presets, or enter your own in kilometres or miles.
2
Enter a target time or a pace
Whichever you know. The other is calculated from it.
3
Check the splits
Per kilometre and per mile, so you can hold the pace with whatever your watch shows.
4
Train slower than this
Most of your weekly running should sit well below the pace shown here.

Questions people ask

How do I calculate running pace?: Divide total time by distance. For a 25 minute 5K that is 25 divided by 5, which is 5 minutes per kilometre. This tool handles the conversions and the unit switching for you.
What pace is a 4 hour marathon?: About 5 minutes 41 seconds per kilometre, or 9 minutes 9 seconds per mile, held for the full 42.2 kilometres.
Should I train at race pace?: Mostly not. Most weekly volume should be comfortably slower, at conversational effort, with a smaller amount of faster work. Training at race pace constantly is a common route to being tired and injured.
Can I predict my marathon time from a 5K?: Not reliably. Prediction formulas assume endurance scales in a way that often does not hold for amateur runners, since the marathon is limited by fuelling and durability rather than speed. This tool deliberately does not guess.