Swim
Critical Swim Speed
Calculate your CSS from a 400m and 200m time trial. Get swim training zones and pace bands.
Open calculatorSwim Pace Converter
Convert swim times between metres and yards. Pace per 100m, 100yd, and projected race times.
Open calculatorSwim Efficiency (SWOLF + DPS)
Calculate SWOLF score, distance per stroke, stroke rate, and pace from a single lap.
Open calculatorCSS from Any Test Set
Estimate CSS from 4x100, 1500 TT, Maglischo T30, or the classic 200/400. Multi-protocol companion.
Open calculatorBike
Bike FTP Calculator
Calculate your FTP from a 20-minute power test. Get Coggan power zones and W/kg.
Open calculatorGear Ratio Calculator
Calculate gear inches, development, and speed for any chainring and cassette combo.
Open calculatorCdA Estimator
Estimate aerodynamic drag area from steady-state power and speed. Martin 1998 model.
Open calculatorClimb Time Calculator
How long will that hill take? Predict time, VAM and equivalent flat pace from FTP, weight and gradient.
Open calculatorRun
Multisport
Race Time Predictor
Predict your finish time for any distance using the Riegel formula.
Open calculatorTransition Time Planner
Estimate your T1 and T2 transition times and find where to save seconds.
Open calculatorNutrition & Hydration Planner
Calculate carbs, fluid, and sodium per hour. Includes sweat rate calculator.
Open calculatorRace-Week Fuelling Planner
7-day fuelling: carb load, breakfast, fibre cap, sodium ramp, alcohol and caffeine, plus race-day g/hr.
Open calculatorIronman & 70.3 Pacing
Target time to splits, or splits to finish time. Full IM, 70.3, Olympic, and Sprint.
Open calculatorBrick Pacing Calculator
First-mile and settled run pace off the bike for sprint, Olympic, 70.3 and Ironman. Built from your open 10k.
Open calculatorSweat-Rate Test
Calculate hourly fluid and sodium loss from a 60-minute weigh-in test. Get personalised drink targets.
Open calculatorTraining & Health
Heart Rate Training Zones
Calculate HR zones using Max HR, LTHR (Friel), or Karvonen methods.
Open calculatorWetsuit Temperature Guide
Check wetsuit rules for BTF, World Triathlon, and Ironman by water temperature.
Open calculatorVO2 Max Estimator
Estimate VO2 max from Cooper, Rockport, or HR reserve tests. Get your fitness classification.
Open calculatorTSS & CTL/ATL Tracker
Calculate Training Stress Score. Project fitness, fatigue, and form over 14 days.
Open calculatorTaper Planner
Generate a science-based taper schedule. Mujika progressive, step, or linear taper.
Open calculatorRecovery Score
Composite HRV + sleep + RHR + RPE readiness score with a rolling 14-day history.
Open calculatorWhy use our calculators?
Accurate formulas
Built on established sports science: Wakayoshi CSS, Coggan power zones, Martin 1998 aero model, Riegel prediction, Friel HR zones, Mujika taper, Sheldon Brown gearing, and governing body rule books.
Free, no sign-up
Every calculator is free to use. No account required. No data stored on our servers.
Save & share results
Copy a shareable link or export your results as text. Share with your coach or training partners.
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