Your fitness data, unlocked
Free tools to calculate your energy needs, analyze Garmin activities, and get more out of your training. No account needed.
TDEE Calculator
Calculate your Total Daily Energy Expenditure with precision. Uses Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas.
FIT File Analyzer
Drop a Garmin FIT or GPX file and get instant analysis — heart rate zones, pace charts, splits, and more.
File Converter
Convert between FIT, TCX, GPX, and CSV formats instantly. 6 converters, all free and private — data never leaves your device.
Workout Builder
Build strength workouts with sets, reps, rest periods, and weights. Export Garmin-compatible JSON and import directly into Garmin Connect.
Pace Calculator
Convert between pace and speed, calculate finish time for any race distance, and generate per-km or per-mile splits. Works for running and cycling.
HR Zone Calculator
Calculate your heart rate training zones using the 220-age, Tanaka, or Karvonen formula. Garmin-compatible 5-zone and 3-zone output.
Split Calculator
Generate even, negative, or positive split strategies for any race distance. See per-km targets and cumulative elapsed times in a handy pace table.
Race Time Predictor
Predict your marathon time from a 5K or 10K result using the Riegel formula. Works for any pair of race distances from 1K to 100K.
Body Fat Calculator
Estimate body fat percentage using the US Navy method or the Deurenberg BMI formula. Shows lean mass, fat mass, and your body fat category.
VO₂max Estimator
Estimate your aerobic capacity from any race result using the Jack Daniels method. Get personalised training paces for all five intensity zones.
Calorie Burn Calculator
Calculate calories burned for 35+ activities including adaptive sports. Uses validated MET values from the Compendium of Physical Activities.
Zone Builder
Build custom HR and power zones with editable names. Includes FTP-based cycling power zones. Copy BPM ranges to enter into Garmin Connect.
Interval Builder
Build running interval workouts with custom reps, distances, and pace targets. Export Garmin Connect JSON to import directly to your watch.
Hydration Calculator
Calculate fluid intake, electrolyte needs, and per-hour hydration targets for training and race day.
Cadence Calculator
Calculate running cadence, stride length, and steps per minute from your pace or height.
Running Power Calculator
Estimate running watts from pace, body weight, gradient, and wind conditions.
Pace Band Generator
Create a printable race pace wristband with per-km or per-mile splits for any race distance.
Race Day Planner
Enter your race and goal time to get a pacing plan, calorie estimate, hydration schedule, gel timing, and a printable gear checklist.
Route Elevation Analyzer
Upload a GPX file to analyze elevation gain, loss, grade, and an interactive elevation profile chart. Identifies cycling climb categories (HC to Cat 4).
Weekly Training Log
Upload multiple FIT, GPX, or TCX files to get a full weekly training summary — total distance, time, elevation, and heart rate stats in one table.
Compound Tools
All-in-one tools that chain multiple calculators — enter once, get everything.
Running Performance Profile
One race result → VO₂max, predictions for all 12 distances, 5 Daniels training paces, HR zones, and exportable interval workouts.
Body Recomp Calculator
Body fat + BMR + TDEE + macros + calorie burn + cutting timeline. All-in-one body recomposition calculator.
Activity Analyzer
Upload FIT, TCX, or GPX for full workout analysis — elevation profile, HR zone distribution, calorie burn, VO₂max estimate, and format export.
Race Day Nutrition Planner
Predicted finish time → calorie burn → 3-day carb loading schedule → per-km fueling timeline → recovery nutrition targets.
Training Week Planner
Enter your race result and goal to get a personalised 7-day plan with pace targets, HR zones, Garmin interval workouts, and strength days.
Multi-File Training Load
Upload up to 5 activities to calculate TSS per session and view your Fitness (CTL), Fatigue (ATL), and Form (TSB) chart.