Bike Split Calculator
Estimate your bike time from power, not guesswork. Enter your FTP, target intensity, position, and course, and a validated cycling power model solves for your speed and split.
Your power & course
Picking a distance sets a typical intensity factor — adjust if you like.
Save your results & get more tips
Download your bike split PDF plus weekly training tips.
Unsubscribe anytime. We respect your privacy.
We earn a commission if you buy through this link, at no cost to you. Learn more
How this calculator works
Target power is FTP × intensity factor. Ground speed is solved from the standard cycling power equation (rolling resistance + gravity + aerodynamic drag) using your total weight, position-based CdA, surface Crr, and average grade. Time is distance divided by speed.
Assumptions
- • Constant power on a constant average grade
- • No wind; sea-level air density (1.225 kg/m³)
- • Position-typical CdA and surface-typical Crr
Limitations
- • Real courses vary; gradient profile matters on hilly routes
- • CdA is an estimate — only a fit/aero test gives your true value
Who this is for
- • Triathletes pacing a bike leg by power
- • Cyclists comparing positions, weight, or surface choices
- • Athletes setting a realistic bike target before a race
Who this is not for
- • Courses with significant rollers, wind, or technical descents
- • Athletes without a known FTP (test first)
References
Related Articles
Continue exploring our comprehensive triathlon resources
Bike Split Calculator FAQ
Scientific References
Validated physics model underlying the speed-from-power calculation