Bicycle Power Calculator

Calculate a mechanical-power scenario from measured motion and explicit resistance, drag, density, wind, and efficiency inputs.

Inputs and method

Rolling force = Crr × mass × 9.80665. Grade force = mass × 9.80665 × grade/100. Aerodynamic force = ½ × density × CdA × relative-air-speed². Wheel power is total force × ground speed; input power divides by efficiency.

All empirical factors, rates, percentages, clearances, product yields, and model values shown as inputs are scenario values supplied by you. Their source or measurement basis appears beside the inputs and result. Units remain visible, calculations use unrounded values, and rounding occurs only for display or a whole-package ceiling.

Interpreting the result

Results are sensitivity arithmetic, not performance, fitness, training, equipment, or safety guidance.

Treat scenario ranges as sensitivity ranges, not confidence intervals. Check the factor’s version, geography, population or product, system boundary, and date before using the result. A finite arithmetic result does not establish code compliance, certification, safety, forecast accuracy, or model validity.

Validation and rounding

Blank required factors, invalid numbers, prohibited negatives, impossible relationships, and unsupported modes do not produce a result. No malformed value silently selects another branch. Continuous outputs use the precision displayed in the result; package quantities round up only after waste is applied.

Worked example

With 75 kg, Crr 0.005, 2% grade, 10 m/s ground speed, 2 m/s headwind, CdA 0.32 m², density 1.204 kg/m³, and 100% efficiency, the components are 3.677 N, 14.710 N, and 27.740 N; input power is 461.3 W.

Frequently asked question

Does this predict cycling performance? No. It reports force and power arithmetic from entered coefficients and measurements, whose uncertainty must be supplied.

Sources

• USA Cycling, “Strength Training for Cyclists” — web article; scope and training-context passages, accessed 2026-07-09. Route-specific boundary: context and terminology only; it does not supply an entered coefficient, uncertainty, recommendation, or approval.
• USA Cycling, “Training Tips with Christopher Blevins” — web article; training-context passages, accessed 2026-07-09. Route-specific boundary: context and terminology only; it does not supply an entered coefficient, uncertainty, recommendation, or approval.
• USA Track & Field, “Road Running” — current web edition; discipline overview, accessed 2026-07-09. Route-specific boundary: context and terminology only; it does not supply an entered coefficient, uncertainty, recommendation, or approval.