Triathlon time calculator
Estimate your total time and three splits, transitions and bike fatigue included, for sprint, olympic, 70.3 or Ironman.
Updated 16 September 2026
A triathlon does not add up like three separate races. The run happens on legs already emptied by the bike, and transitions cost more than people expect.
This calculator applies the correction the estimators we reviewed leave out: bike fatigue on the run, plus the transitions.
1.5 km · 40 km · 10 km
Your average on a sustained ride
Between 8 and 25 km/h
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How it is computed
The swim starts from your pace per 100 metres applied to the format’s distance. The bike starts from your average speed. Both are proportional and require no assumption.
The run starts from your VMA with the sustainable percentage for the distance, then takes an 8 % penalty for bike fatigue. That correction is what is missing almost everywhere else.
Transitions are budgeted at 5 minutes total for T1 and T2. That is realistic for an amateur on a short format; on an Ironman, expect 8 to 12 minutes if you change fully.
The plans built from this number
Now the plan that goes with it
These numbers are exactly the ones Endu uses to build a full preparation: phases, volume, detailed sessions, exported to your watch. 14-day trial, cancel any time.
Create my planFrequently asked questions
- Why an 8 % run penalty?
- It is the order of magnitude observed between a standalone run time and the same effort off the bike, in a properly trained athlete. Without brick sessions in training the gap is considerably larger — which is precisely what bricks exist to reduce.
- Will my actual time be slower?
- Often a little, and almost always for the same reasons: an open-water swim slower than the pool, unrehearsed transitions, and insufficient fuelling on long formats. On an Ironman, the gap between estimate and reality is mostly decided by nutrition.
- How do I know my race bike speed?
- Take your average speed on a long ride at sustained intensity, not your best ride. In a race, a flat course adds 1 to 2 km/h and a hilly one takes as much away. If you have an FTP, the power calculator gives a firmer marker.
- Does it work for a first triathlon?
- Yes, but add a margin: on a first event, transitions, the mass start and open-water swimming easily cost 5 to 10 minutes more than the estimate. Aim to finish, not to hit a time.