Power - Time Calculator
Estimate time or required power for a segment. Includes realistic effort estimation based on your power profile.
How the Power-Time Calculator Works
This tool solves a common question every road cyclist and time trialist faces: "How long will it take me to ride this segment at a given wattage?" - or the other way around - "What power do I need to hold to finish in a specific time?"
The calculator uses a physics-based model that balances the power you put into the pedals against the main resistive forces acting on a rider: aerodynamic drag, gravity on the gradient, rolling resistance (Crr) and drivetrain losses. Air density is derived from the altitude and temperature you enter, so high-altitude or hot-weather scenarios produce realistic results.
CdA (drag area) is the single biggest factor on flat and rolling terrain. A typical road cyclist on the hoods sits around 0.32-0.38 m², while a well-fitted time trial position can drop below 0.25 m². Even small changes - removing a loose jersey or tucking your elbows - can save minutes over a long course. If you do not know your CdA, the default of 0.30 is a reasonable starting point for a road rider in the drops.
On steep climbs the gradient dominates, and watts per kilogram (W/kg) becomes the metric that matters. The calculator shows VAM (Vertical Ascent rate in Meters per hour) alongside finish time so you can benchmark your result against well-known climbs. For example, a VAM above 1,500 m/h on a sustained climb is world-class.
If you are logged in and have a rider profile with FTP and W' set, the tool also estimates your best realistic effort for the segment. It uses the Critical Power model to figure out how much above FTP you can sustain for the required duration, giving you a practical pacing target on race day.