Bike Gradient Power Calculator

Ride inputs

Speed km/h

Gradient %

Total weight (rider + bike + gear) kg

Aerodynamics

Riding position

Drag area, CdA m²

Wind speed km/h, headwind +

Rolling resistance

Surface / tyres

Rolling resistance coefficient, Crr

Air & drivetrain

Altitude m

Air temperature °C

Drivetrain efficiency %

Result

Component	Force (N)	Power (W)

Graph

Hover or tap the chart to read exact values. Each family is read on its own x-axis, so the two lines under the crosshair give different speed/power pairs.

Gradient— Speed line— Power line—

Speed lines — power needed vs gradient, at fixed speed (bottom axis: power) Power lines — speed achieved vs gradient, at fixed power (top axis: speed) Bold line = your current inputs

How this was calculated

This uses the standard cycling physics model (gravity + rolling resistance + aerodynamic drag, scaled up for drivetrain loss). It's my best estimate of the formula from your spreadsheet — swap in calculatePower() in app.js once the real spreadsheet formula is available.