The Triathlon Split Training Load Calculator estimates a combined workload from swim, bike, and run duration plus a separate intensity factor for each discipline. It is designed for triathletes who want one session-level load number while preserving the different contribution of each leg. Each discipline uses the same duration × intensity-squared structure, and the three loads are then added together.
An intensity factor of 1.00 means the session segment was performed at your chosen threshold reference, while lower or higher values represent easier or harder relative intensity. Because threshold definitions differ between swimming, cycling, and running, set each factor from the method you already use for that sport rather than assuming they are interchangeable. The result is a planning index, not an official training platform score, and it does not directly model transitions, heat, elevation, technique, strength work, or accumulated fatigue.
Calculator inputs
min
min
min
Result
—
Estimated result
Swim load—
Bike load—
Run load—
Total duration—
1. Enter swim duration and intensity Use minutes plus a swim-specific intensity factor relative to your chosen swim threshold reference.
2. Enter bike duration and intensity Add cycling minutes and a bike-specific intensity factor, commonly based on your cycling threshold metric.
3. Enter run duration and intensity Provide running minutes and a run-specific intensity factor from your usual training method.
4. Review total load The main result is the sum of the three discipline loads.
5. Inspect split contributions Use the individual load values to see which discipline drove the session most strongly.
Swim load = Swim hours × Swim IF² × 100
Bike load = Bike hours × Bike IF² × 100
Run load = Run hours × Run IF² × 100
Total triathlon load = Swim load + Bike load + Run load
Each intensity factor is relative to a discipline-specific threshold reference. The method uses a common mathematical structure so the three components can be summarized consistently, but it is not an official cross-sport equivalence standard.
What the result means
The total is a relative workload index for the combined session, while the discipline rows show how much each split contributes.
Compare loads mainly within your own training history. Different threshold tests and devices can change intensity factors and therefore the score.
Given: Swim: 45 min at IF 0.85; bike: 120 min at IF 0.78; run: 60 min at IF 0.82.
Interpretation: The bike contributes about half of the combined load because it is the longest segment, while swim and run add substantial but smaller shares.
What does an intensity factor of 1.0 mean?
It means the segment is performed at the threshold reference you use for that discipline. The exact physiological meaning depends on how that threshold was defined.
Can one discipline have a duration of zero?
Yes. A zero duration contributes zero load, so the calculator can also be used for brick sessions with only two disciplines.
Should swim, bike, and run intensity factors come from the same test?
No. Each sport should use its own appropriate threshold or reference method because pace, power, and heart-rate relationships differ.
Why square the intensity factor?
Squaring makes harder work contribute disproportionately more load. It is a deliberate modeling choice used here for consistent comparison.
Is this the same as Training Stress Score or another branded metric?
No. The structure is similar to common duration-and-intensity load models, but this calculator is a generic planning estimate and should not be treated as a branded or platform-identical score.