Calculators
25 free calculators for training and race planning.
🏃Running
Pace Calculator
Calculate time ↔ pace ↔ distance.
Race Predictor
5K → 10K → half marathon → marathon via the Riegel formula.
VDOT Calculator
Jack Daniels formula → VDOT + all training paces.
Training Zones
HR zones from lactate threshold heart rate.
Splits Calculator
Plan even or negative splits.
Elevation Pace
Pace adjustment for grade (Minetti formula).
Age Grading
Compare performance adjusted for age (WMA).
Treadmill Calculator
Treadmill ↔ road run equivalent.
🚴Triathlon & Endurance
Triathlon Time
Calculate total time including transitions.
FTP Calculator
20-min test or ramp test → FTP + zones.
Cycling Power
Calculate and classify watts/kg.
Race Nutrition
Carbs, fluid and sodium per hour.
TSS Calculator
Training Stress Score for bike, run & swim.
TRIMP
HR-based training load per Banister.
VO2max Calculator
Cooper test, HR ratio, or Rockport walk.
HR Zones
Heart rate training zones from max HR or LTHR.
BMI & Body Fat
BMI, Deurenberg, and US Navy method.
Sleep Needs
Calculate optimal sleep for athletes.
🏋️Strength Training
⭐Special — Ambitious Athletes
Marathon Training Paces
Target time → all training paces (race, tempo, easy).
GP Bern Forecast
GP Bern time (10 miles) → 5K, 10K, half marathon, marathon.
Taper Calculator
Plan training reduction before the race.
Carb Loading
Optimize glycogen stores before competition.
Sweat Rate
Individual sweat rate and hydration strategy.
Which calculator helps with what?
The collection covers four areas. For pace and times: pace, splits, race predictor and the triathlon time calculator. For your capability: FTP, VDOT, VO2max, training zones and TSS.
Then everything around race day — fuelling, carb loading, sweat loss, tapering — plus a small section for strength training.
All calculators are free and need no account. Your entries stay in the browser and are not stored anywhere.
Where to start
If you are new: the pace calculator and training zones. Those tell you how fast you are going and how hard a session should be — nothing more is needed at first.
If you are building towards a race: race predictor for the goal time, splits for pacing, race nutrition for fuelling and the taper calculator for the final weeks.
Frequently asked questions
- Are the calculators free?
- Yes, all of them. No account, no sign-up. An account only becomes worthwhile once you want to track your sessions over time.
- Are my entries stored?
- No. The calculators run in your browser and the values never leave your device.
- How accurate are the results?
- It depends on the calculator. Pure conversions such as pace or splits are exact; estimates such as VO2max or predictions are approximations. Each page says what to watch out for.