Calculator library
Choose the decision you need help with.
Free triathlon, swim, bike, and run calculators built around practical training and race-day decisions, backed by published research.
Triathlon
Race planning, split strategy, and multisport decision support.
Use triathlon calculators when you need better race-day decisions, not just more numbers.
Swim
Threshold pace, efficiency, and pacing tools for pool and open-water preparation.
Swim tools should help you pace and train better, not bury you in abstractions.
Bike
Threshold power, training load, and bike pacing support for triathletes.
Bike metrics matter most when they improve pacing discipline and protect the run.
Run
Race-derived pacing and run fitness tools for triathletes and runners.
Run tools should convert race evidence into practical training guidance.
Race Time Calculator
Plan swim, bike, run, and transition splits with research-informed defaults and clearly labeled race-day estimates for fatigue and fueling.
Inputs: Race format • Swim pace • Bike speed, power, or FTP-based effort • T1 and T2 • Temperature, fueling, and sweat assumptions
Ironman Pace Calculator
Plan Ironman swim pace, bike speed, run pace, and transition budgets from a finish-time goal or known splits. Includes sub-12 through sub-9 benchmarks, what-if analysis, and pacing realism guidance.
Inputs: Goal finish time or known split assumptions • Swim pace or split • Bike speed or split • Run pace or split • T1 and T2 • Unit system, experience, and race temperature
70.3 Pace Calculator
Plan 70.3 swim pace, bike speed, run pace, and transition budgets from a finish-time goal or known splits. Includes sub-8 through sub-4:30 benchmarks, what-if analysis, and pacing realism guidance.
Inputs: Goal finish time or known split assumptions • Swim pace or split • Bike speed or split • Run pace or split • T1 and T2 • Unit system, experience, and race temperature
Pace Converter
Convert between pace, speed, and time across swimming, cycling, and running with instant format switching, race projections, and triathlon context.
Inputs: Sport mode • Pace or speed or distance + time • Unit preference
VO2max Calculator
Estimate VO2max across swim, bike, and run field tests, compare the outputs in one place, and keep the confidence level of each method visible.
Inputs: Sport selection • Field test or race result • Age and weight • Resting heart rate
CSS Calculator
Calculate critical swim speed from two swim efforts and turn it into triathlon-ready threshold pacing guidance.
Inputs: Two maximal swim efforts • Pool length • Course assumptions
Swim Pace Calculator
Convert swim times into pace, speed, and race splits with context that makes sense for triathletes.
Inputs: Distance • Time • Course type
SWOLF Calculator
Track SWOLF, stroke count, stroke type, and pool-session pace with watch-aware context that helps triathletes compare scores more honestly.
Inputs: Pool length • Stroke type • Split time • Stroke count
FTP Calculator
Estimate functional threshold power and turn it into cleaner bike zones, Sweet Spot targets, and triathlon pacing anchors.
Inputs: Test protocol • Power result • Weight • Reference band
Bike TSS
Calculate bike Training Stress Score, Intensity Factor, and target ride stress with cleaner load guidance for self-coached triathletes.
Inputs: Duration • Normalized power • FTP • Average power (optional) • Target TSS mode
Power-to-Weight
Calculate your watts per kilogram, see where you rank against cycling and triathlon benchmarks, and get race-specific context for every triathlon distance.
Inputs: Power (watts) • Body weight (kg or lbs) • Gender
Gear Ratio
Calculate gear ratio and speed at any cadence, compare gearing options, and get triathlon-specific cadence and gear-selection advice.
Inputs: Chainring teeth • Rear cog teeth • Cadence (RPM) • Wheel size • Speed unit
Swim TSS
Calculate swim Training Stress Score from session pace and CSS threshold to quantify training load, plan recovery, and balance swim stress within triathlon training.
Inputs: Total swim time • Average pace per 100m • CSS pace per 100m
VDOT Calculator
Turn a recent race result into practical run training paces, track splits, equivalent performances, and triathlon-aware interpretation.
Inputs: Recent race distance • Recent race time
Run TSS
Calculate run Training Stress Score from session pace and threshold pace to quantify run load, plan recovery, and balance run stress within triathlon training.
Inputs: Total run time • Average pace per km • Threshold pace per km
Power Zones
Enter your FTP to see all 7 Coggan power zones with watt ranges, training purpose, example workouts, and triathlon pacing context.
Inputs: FTP (watts) • Body weight (optional) • Unit preference
Nutrition Calculator
Estimate your race-day carbs, fluid, and sodium needs for Sprint, Olympic, 70.3, and IRONMAN triathlon. Includes segment breakdowns, product planning, and fueling timeline.
Inputs: Race type • Duration (swim, T1, bike, T2, run) • Body weight • Experience level • Gut tolerance • Sweat rate • Temperature • Humidity • Carb target mode • Product details (optional)
Swim Calorie Burn
Estimate calories burned swimming using MET values from the 2024 Adult Compendium of Physical Activities. Includes stroke-specific MET data and open-water adjustments.
Inputs: Body weight • Duration • Stroke type • Intensity • Water condition • Wetsuit (yes/no) • Distance (optional)
Bike Pace
Calculate cycling time, speed, or pace for any distance, with race presets for Sprint, Olympic, 70.3, and IRONMAN. Includes course, wind, and bike-type adjustments.
Inputs: Distance • Speed or time or pace • Unit preference (km/mi, km/h/mph) • Course type (optional) • Wind (optional) • Bike type (optional)
Heat Adjustment
Estimate how heat and humidity affect your triathlon race time across swim, bike, and run. Includes hydration and pacing recommendations based on heat index.
Inputs: Temperature (°C) • Humidity (%) • Race distance • Acclimatization status • Base swim/bike/run times
Race Cutoff
Check whether your projected swim, bike, and run splits will clear official race cutoffs for Ironman (17h), 70.3 (8:30), and Olympic events.
Inputs: Race type • Projected swim time • Projected bike time • Projected run time • Transition times
Run Off Bike
Predict how cycling fatigue degrades your run pace in a triathlon. See km-by-km pace decay, settling distance, and tips to minimize the brick effect.
Inputs: Standalone run pace • Bike intensity (% FTP) • Race distance • Brick training frequency
HR Zone Calculator
Calculate your personal training heart rate zones using 4 scientifically validated methods: %HR Max, Karvonen (HRR), Joe Friel (LTHR), and Maffetone MAF. Compare methods side-by-side.
Inputs: Age • Resting heart rate • Maximum heart rate (measured or estimated) • Lactate threshold heart rate (for Friel method) • Calculation method selection
Tire Pressure
Evidence-based tire pressure recommendations using Silca and SRAM research. Accounts for rider weight, tire width, tubeless/tubed setup, hookless rims, and road surface quality.
Inputs: Total system weight (rider + bike + gear) • Tire width (mm) • Tire type (tubeless / tubed) • Rim type (hooked / hookless) • Road surface quality • Weather conditions
Race Predictor
Predict your finish time for any race distance using Riegel and Cameron models. See confidence intervals and a multi-distance comparison table based on a known performance.
Inputs: Known race distance and finish time • Target race distance • Experience level • Age (optional)
OW Swim Pace
Convert your pool CSS or pace to expected open-water performance. Accounts for wetsuit, drafting, water conditions, sighting, temperature, and course type.
Inputs: Pool pace per 100m (or CSS) • Wetsuit (yes/no) • Drafting ability • Water conditions and temperature • Sighting frequency • Course type and race distance
Cadence Calculator
Find your optimal cycling cadence for any terrain and race distance. Calculate speed from cadence and gearing with triathlon-specific run-preservation guidance.
Inputs: Current cadence (optional) • Power output • Terrain type • Race distance / format • Chainring and cog teeth • Wheel circumference
Training Zones
Calculate training zones for swim, bike, and run in one unified dashboard. Uses your CSS, FTP, and VDOT data to generate a complete multi-sport training reference.
Inputs: Swim: 200m and 400m time trial times • Bike: FTP test protocol and average power • Run: Recent race distance and time • Body weight
Bike Split
Plan triathlon bike splits using power-based pacing. Get per-segment time estimates, nutrition timing, and TSS projections for any course profile.
Inputs: Race distance (km) • FTP (watts) • Target effort (% FTP) • Rider + bike weight • Terrain profile
Transition Time
Estimate realistic T1 and T2 transition times based on your equipment, experience, and race setup. Get prioritized time-saving tips ranked by impact and difficulty.
Inputs: Race format • Experience level • Wetsuit (yes/no) • Cycling shoe setup • Equipment choices (helmet, race belt, elastic laces) • Practice frequency
Pace Zones
Calculate running training pace zones using Daniels VDOT and Joe Friel methods. Includes RPE mapping, workout-type recommendations per zone, and weekly volume distribution.
Inputs: Recent race distance and time • Zone methodology (Daniels / Friel / both)
Swim Zones
Calculate swim training zones using CSS-based and Swimsmooth methods. Includes training set suggestions, stroke rate guidance, RPE mapping, and weekly volume distribution.
Inputs: 200m time trial result • 400m time trial result • Zone methodology (CSS / Swimsmooth / both)