Training Calculators
Data-driven tools built from real training algorithms. The same calculations I use for my own marathon, Ironman, and HYROX preparation.
Race-Specific
Calculators designed for specific race formats
HYROX Pace Calculator
Division-Specific Pacing
Calculate running splits and station time targets for HYROX. Division-specific pacing with strength profile adjustments.
Try Calculator for FreeTriathlon Race Time Estimator
Estimate Sprint to Ironman finish times from your swim CSS, bike FTP, and easy run pace. Shows realistic best-to-conservative ranges.
Try Calculator for Free NewIronman Race TSS Planner
Reverse-calculate your target bike watts, run pace, and swim pace from a TSS budget. Science-backed pacing for 70.3 and full Ironman.
Try Calculator for FreePace & Prediction
Predict race times and calculate optimal pacing
VDOT Calculator
Calculate your VDOT from any race result. Get training paces for all 5 Daniels zones and predict equivalent race times.
Try Calculator for Free Coming SoonMarathon Pace Calculator
Calculate splits and pacing strategy for any distance from 5K to ultramarathon.
Coming Soon Coming SoonRace Time Predictor
Predict finish times using Riegel formula, VDOT, and CTL-adjusted methods.
Coming Soon Coming SoonBoston Cutoff Tracker
Track your BQ buffer, see cutoff projections, and get age-up predictions.
Coming SoonTraining Zones
Calculate your training zones for structured training
Training Zones Calculator
Calculate HR, pace, and power zones using Karvonen, %Max HR, or LTHR. Compare Strava vs Garmin vs TrainingPeaks.
Try Calculator for FreeHeart Rate Zones
Calculate HR zones from max heart rate or lactate threshold heart rate.
Try Calculator for Free Coming SoonMarathon HR Pacer
Heart rate-based marathon pacing with terrain and weather adjustments.
Coming SoonNutrition & Hydration
Science-based fueling and hydration tools for race day and training
Endurance Fueling Planner
Division-Specific Pacing
Plan your race nutrition: carbs, fluid, and sodium per hour with a 20-minute execution checklist. Brand-agnostic, based on IOC and ACSM guidelines.
Try Calculator for FreeSweat Rate Calculator
Calculate your sweat rate from pre/post-exercise weigh-ins. Get fluid deficit %, sweat classification, and replacement recommendations.
Try Calculator for FreeRace Day Nutrition Planner
Duration-tiered carb recommendations with sport-specific fluid targets. Includes gut training guidance and execution plan.
Try Calculator for FreeElectrolyte Calculator
Estimate sodium, potassium, and magnesium needs based on sweat rate and saltiness. Personalized electrolyte strategy.
Try Calculator for FreeGlycogen Depletion Calculator
Predict when you'll bonk: estimate glycogen stores, depletion time, and carb intake needed to extend performance.
Try Calculator for FreeCycling Power
FTP analysis, power profiling, and cycling performance tools
FTP Percentile Calculator
Division-Specific Pacing
See where your FTP ranks among cyclists your age and gender. Interactive bell curve, Coggan power levels, and personalized advice to reach the next level.
Try Calculator for FreeFTP Calculator
Calculate your Functional Threshold Power from a 20-minute test, ramp test, or 8-minute protocol.
Try Calculator for FreeWatts per Kg Calculator
Convert between absolute watts and power-to-weight ratio. See where your W/kg falls on the cycling scale.
Try Calculator for Free NewPower-Speed Calculator
Enter power, weight, CdA, and gradient to find your expected speed. Same physics as Best Bike Split — no subscription.
Try Calculator for Free NewCdA Estimator
Estimate your aerodynamic drag area from a flat-road field test. Power, speed, weight, and Crr — no wind tunnel needed.
Try Calculator for Free NewIndoor Bike Fit Calculator
Saddle height (LeMond method) and handlebar reach for spin bikes, Peloton, Technogym, and other indoor trainers — from your height and inseam.
Try Calculator for Free NewTechnogym Group Cycle Setup Calculator
The 4 notch numbers for a Technogym Group Cycle — saddle height, saddle fore/aft, bar height, bar reach — scaled from a real, verified fit.
Try Calculator for Free NewPeloton Bike Fit Calculator
Saddle height and handlebar reach for the Peloton Bike/Bike+, mapped to Peloton's own cm markings.
Try Calculator for Free NewKeiser M3i Bike Fit Calculator
Saddle height and handlebar reach for the Keiser M3i, mapped to its post markings.
Try Calculator for Free NewStages SC3 Bike Fit Calculator
Saddle height and handlebar reach for the Stages SC3 studio bike.
Try Calculator for Free NewLife Fitness IC7 Bike Fit Calculator
Saddle height and handlebar reach for the Life Fitness IC7 studio bike.
Try Calculator for FreeAll Calculators by Category
Browse the full library, including tools not featured above.
Running
Pace calculators, race predictors, and training tools for runners.
Cycling
Power, FTP, gear ratio, and cycling-specific calculators.
Swimming
Swim pace, CSS, and pool training calculators.
Triathlon
Race estimators, transition tools, and multi-sport calculators.
HYROX
HYROX race pace, station times, and event-specific calculators.
Strength
One-rep max, strength standards, and lifting calculators.
Nutrition
TDEE, macros, calorie deficit, and sports nutrition calculators.
Heart Rate & Zones
Heart rate zone calculators for training by HR, power, or pace.
Recovery
TSS, training load, and recovery tracking calculators.
General Fitness
VO2max, fitness tests, calorie burn, and general training tools.
Real Algorithms, Real Results
These calculators are ported from the training analysis system I built for my own marathon and Ironman preparation. They use the same algorithms used by professional coaches and sports scientists.