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70.3 / Half Ironman Predictor

Predict your Half Ironman 70.3 finish time.

Enter sustainable training paces for each discipline and we'll model realistic swim, bike, and run splits plus transitions. Toggle between metric and imperial (US) units. Numbers update live.

Units
Predicted 70.3 finish
5:15:35
Swim 1.9 km
34:50
T1
4:00
Bike 90 km
2:48:45
T2
2:30
Run 21.1 km
1:45:30

How to enter race-realistic paces

  • Swim: use your CSS pace (Critical Swim Speed), not 100m max effort.
  • Bike: the speed you can hold at ~75–80% of FTP for 2h30 on race terrain.
  • Run: open half-marathon pace + 15–30 sec/km (or +24–48 sec/mi) for off-the-bike fatigue.

Want a full 24-week 70.3 plan?

Our 24-week Half Ironman program is built by an RRCA/USAT-certified coach and used by athletes targeting sub-5h and sub-4:30 70.3 finishes.

Need full Ironman splits too?

Use the full distance calculator that covers Sprint → Ironman.

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