Upload a GPX route to estimate your finish time based on power and conditions.
Yes. You get course-specific pacing from a GPX file using the same core physics model that paid planners like Best Bike Split rely on. This tool is free, runs in your browser, and has no account requirement. Paid services add features like live weather forecasting and Garmin or Wahoo race-day integration. If you want accurate time and power predictions for a specific course without paying a subscription, this covers it.
The physics model captures the four main forces acting on a rider: aerodynamic drag, rolling resistance, gravity, and drivetrain friction. With reasonable estimates of your CdA, Crr, and weight, predictions are typically within 3-5% on flat or rolling courses. Larger errors usually come from unknown wind on race day or a poorly estimated CdA.
Any standard GPX 1.0 or 1.1 file with track points and elevation data. Exports from Strava, Komoot, RideWithGPS, Garmin Connect, and Wahoo all work, as do files from course-builder sites like bikeroutetoaster and plotaroute.
Yes. The race-intensity presets map to common durations: All-out (under 1h) for sprint triathlon or short time trial, Hard (1-2h) for Olympic distance, Steady (2-4h) for Half Ironman or gran fondo, and Endurance (4h+) for full Ironman or ultra-distance. Pick the preset closest to your target and fine-tune from there.
FTP (Functional Threshold Power) is the power you can sustain for about an hour. You can skip it and set climb and flat watts directly. Entering your FTP makes the intensity presets more useful by scaling power targets to the expected race duration.
CdA is your drag coefficient multiplied by frontal area, measured in m². It captures how aero you are. Rough reference values: tops ~0.38, hoods ~0.32, drops ~0.30, time-trial clip-on bars ~0.27, pro TT position with skinsuit and aero helmet ~0.20. The 'How does this work?' panel on the tool page has the full table.
Yes. Set a headwind or tailwind in km/h and it gets factored into the aerodynamic drag calculation. Live weather forecasting is not included yet, so check the forecast closer to race day and enter the expected wind manually.
No. The GPX parsing, physics, and your saved preferences all run in your browser. Nothing is uploaded to any server.