Triathlon performance platform
Science-backed calculators for triathletes who train by numbers.
Triathlon Regimen helps you turn swim, bike, run, and race-day metrics into clearer pacing decisions, cleaner training anchors, and more practical planning.
Why this site exists
Better decisions beat bigger dashboards.
Plan race-day pacing with transitions and split tradeoffs in view.
Set swim, bike, and run training anchors without guessing.
Understand what the metric means before you let it change your training.
Built around real race decisions
Every calculator focuses on pacing, thresholds, and split planning that triathletes can actually use on race day.
Research-backed methodology
Formulas and benchmarks are grounded in published endurance-sport research with sources cited on every page.
Privacy-first, no ads
Lightweight, fast, and free. Minimal analytics for site improvement only. No ads, no account required.
Featured calculators
Start with the metrics that actually move decisions.
Plan race-day splits, set training anchors, and compare your performance against real age-group benchmarks.
Race Time Calculator
Plan swim, bike, run, and transition splits with research-informed defaults and clearly labeled race-day estimates for fatigue and fueling.
Map realistic race-day splits for sprint through long-course triathlon with explicit assumptions around swim conditions, bike execution, and run durability.
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.
Use a dedicated long-course planner to turn Ironman goal times or known splits into realistic swim, bike, run, and transition targets with benchmark context and athlete-safe pacing guidance.
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.
Use a dedicated half-distance planner to turn 70.3 goal times or known splits into realistic swim, bike, run, and transition targets with benchmark context and athlete-safe pacing guidance.
Pace Converter
Convert between pace, speed, and time across swimming, cycling, and running with instant format switching, race projections, and triathlon context.
Use one tool to translate pace into every format you need — per 100m, min/km, min/mile, km/h, mph — across all three triathlon disciplines.
CSS Calculator
Calculate critical swim speed from two swim efforts and turn it into triathlon-ready threshold pacing guidance.
Use CSS to anchor threshold swim pace, structure sets, and interpret race-pace readiness with more confidence.
Swim Pace Calculator
Convert swim times into pace, speed, and race splits with context that makes sense for triathletes.
Use pace conversion and split views to make pool sets, open-water estimates, and race planning easier to compare.
FTP Calculator
Estimate functional threshold power and turn it into cleaner bike zones, Sweet Spot targets, and triathlon pacing anchors.
FTP is most useful when it helps you train well and pace the bike without wrecking the run.
VDOT Calculator
Turn a recent race result into practical run training paces, track splits, equivalent performances, and triathlon-aware interpretation.
VDOT works best when it turns current race evidence into useful pace guidance without pretending that triathlon running happens on fresh legs.
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.
Plan your race-day nutrition with carb, fluid, and sodium targets based on race duration, conditions, gut tolerance, and experience level.
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.
Determine precise heart rate training zones using multiple methodologies, compare them side-by-side, and print a pocket-sized zone card for workouts.
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.
Get optimal front and rear tire pressures backed by modern rolling resistance research. Lower is often faster on real roads.
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.
Enter a known race result and get scientifically modeled predictions for any target distance with confidence ranges and pace breakdowns.
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.
Get a realistic open-water pace prediction from your pool performance with a detailed breakdown of every environmental factor affecting your swim.
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.
Enter your threshold data for all three disciplines and get a complete, printable training zone card covering swim pace zones, bike power zones, and run pace zones.
Discipline hubs
Calculators organized by discipline.
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.
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