Free tools
Resources
Free physics-based calculators for cyclists, runners, and triathletes — predict speed from power, compare equipment choices, map your gears, and plan ride times. No sign-up required.
Bike Calculator
Predict your cycling speed from power output — or the power a given speed requires. A physics model accounting for gravity, wind resistance, and rolling resistance.
Comparison Calculator
Compare two bike setups side by side. See exactly what a lighter bike, a more aero position, or better tires is worth in speed — or in watts saved.
Route Time & Fueling Calculator
Upload a GPX or FIT route and predict your ride time from FTP and weight, segment by segment — plus TSS, calories, and how many carbs per hour to eat.
Bike Gear Calculator
Map every gear on your drivetrain — ratios, gear inches, meters of development, and speed at cadence. Spot overlapping gears and check derailleur capacity.
Want a full training plan?
Create an account for a full periodized plan built around your race calendar and fitness.