Duathlon finish time calculator

Put in your run, bike and run paces for each leg and the time you lose in transition, and see your finish.

Your details

Predicted finish

1:25:30

5.0 km run, 20 km bike, 2.5 km run

Run 127:30
Bike40:00
Run 215:00
Transitions3:00

The second run is where duathlons are decided. Starting the first run a little easier than feels right usually makes the whole race faster.

The working

A sprint duathlon

5 km at 5:30 is 27:30. 20 km at 30 km/h is 40:00. 2.5 km at 6:00 is 15:00. Three minutes of transitions makes 1:25:30.

The second run

Where it gets real

Legs feel heavy off the bike, so the second run is usually slower even though it is shorter. Leave the blank for run 2 and we add 5% to your first run pace.

Good for beginners

No swim needed

A great first multisport race
Any bike will do for a local sprint
Practise a short run straight after a ride
Check helmet and bike rules in advance

Read with care

What this cannot tell you

CourseHills and wind change bike times a lot.
PacingRacing run 1 too hard costs more later.
HealthFeeling faint or chest pain: stop and get help.

Questions

Common questions

What is a duathlon?

A run, a bike and another run, back to back.

How long is a sprint duathlon?

Usually 5 km run, 20 km bike, 2.5 km run.

Is a duathlon harder than a triathlon?

Different: no swim, but two runs.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.

Before you push on

New to exercise, or got a heart, lung or joint condition? Have a word with your GP or practice nurse first. Stop and get help if you feel chest pain, faintness or unusual breathlessness, and call 999 if it is severe.