triathlon race time predictor
Triathlon Race Time Predictor
Enter the thresholds you already train with — FTP, run threshold pace, swim CSS — and get a realistic finish-time range with conservative, target and stretch times, swim/bike/run splits with target power and pace, an estimate of your transitions, and an honest read on how much to trust it.
Race type
This band narrows as your training data sharpens.
- Course profile — upload a GPX below for a course-aware bike split
- Race-day weather — unlocks with an uploaded course; we look up typical conditions for your race date
- T1/T2 transition time is included in the total
- Running off the bike — the run split pays for this distance's bike intensity
- Bike-plan reality check — unlocks with regular rides carrying power data over the last 3 months
- Late-race endurance — unlocks with 90+ minute sessions in the last 3 months
- Personal tuning — confirm your result after each race; every one sharpens future projections
- Open-water swim — assumes a wetsuit-legal swim; wetsuit buoyancy and open-water conditions (sighting, crowds) are both priced inAssumes a wetsuit-legal open-water swim: wetsuit buoyancy typically buys ~5% on pool pace, while sighting and crowds cost some back (also priced in). If your race bans wetsuits, expect the swim a touch slower.
How to use it
- 1
Pick your race: sprint, Olympic, 70.3, or Ironman — or a standalone 5K, 10K, half, or marathon.
- 2
Enter your FTP (watts) and body weight, and choose a road or TT/tri bike setup.
- 3
Enter your run threshold pace (your roughly one-hour race pace per km).
- 4
Enter your swim CSS (critical swim speed) per 100 m — use the CSS calculator if you don't know it.
- 5
Read your conservative/target/stretch finish, per-leg splits with target power and pace, and your estimated transitions.
Not another flat finish-time formula
Most predictors apply one Riegel exponent to a single input and hand you a single number. This runs the same model PaceBeats uses inside the app: the bike leg solves the aerodynamic drag and rolling-resistance equation for the speed your race power produces, the swim adds distance degradation plus an open-water wetsuit adjustment, and the run stacks a distance factor with a triathlon run-off fatigue multiplier — because a 70.3 half-marathon off the bike is nothing like an open half-marathon.
A range, not a false-precision number
Real races land in a window, so this gives you one: a conservative, target and stretch finish built from a confidence band, not a single time pretending to be exact. The width is driven by how much the model can trust your inputs — three solid thresholds tighten it, a missing one widens it — and each triathlon estimate folds in the transitions most calculators quietly ignore.
The product predictor, with honest cold-start defaults
This is the in-app forecast running on only what you can type here. The signed-in version layers on what a logged-out visitor can't provide — your training history, long-run durability, race-day climate, course elevation and outcomes it has learned from — to tighten the range further. Because you're typing your thresholds rather than having them tested, it reads them as honest self-reported values: current, but capped at an estimate tier that a dated fitness test would beat.
Common questions
How accurate is the triathlon time predictor?
On a flat-to-rolling course in fair conditions the target time is typically within a few percent for athletes who enter accurate thresholds — and it hands you a conservative-to-stretch range rather than a single guess, so you can pace to the band. It doesn't yet model course elevation, wind, heat, or your pacing discipline from typed inputs alone, so treat the range as a well-grounded target rather than a guarantee — and trust it most, with a tighter band, when all three thresholds are entered.
Why does it show a range instead of one time?
Because an honest prediction is a window, not a point. The band widens or tightens with how much the model can trust your inputs: three fresh thresholds give a narrow range and a high-confidence read, while a missing threshold or a self-reported one widens it. Signing in narrows the band further using your training history and past race outcomes.
What's the difference between this and a Riegel calculator?
A Riegel calculator extrapolates one known time to another distance with a fixed exponent. This predictor models each discipline from your physiological thresholds and the physics of cycling, adds the triathlon-specific run-off fatigue and transitions a single-sport formula can't capture, and expresses the result as a calibrated range with a confidence tier.
Related tools
Keep going
Next step
Turn these numbers into an adaptive plan.
PaceBeats combines the relevant calculations with your training history, constraints, and deterministic checks to build and adapt your week.