Box Hill Time Calculator
Box Hill was featured in the 2012 London Olympics road race and is a popular training climb for London-area cyclists. The Zwift version captures the famous zigzag ascent through the North Downs.
Elevation Profile
2.98km
136m
8m → 144m
4.4%
Max: 10.0%
Your Profile
Based on FTP ÷ Weight
Estimated Time
11:44
Estimated Completion Time
15.2 km/h
Avg Speed
203W
Avg Power
143 kJ
Energy
20
TSS
Section Breakdown
Performance Benchmarks
Your Estimated Performance
2.67 W/kg
Estimated Time
11:44
Accurate Segment Time Predictions
Our segment calculator uses Zwift-specific physics for precise time estimates.
Zwift Physics Engine
Uses Zwift's actual CdA, rolling resistance, and gradient physics.
Detailed Elevation Profile
See the full segment profile with gradient zones color-coded.
Section Breakdown
View time estimates for each section of longer climbs.
W/kg Benchmarks
Compare your estimated time against standard performance levels.
Training Metrics
See TSS, kilojoules, and average power for the segment.
Related Segments
Discover similar segments for your next training session.
How the Segment Time Calculator Works
Get accurate time predictions for any Zwift segment in three simple steps.
Enter Your Profile
Input your FTP, weight, and height to calculate your W/kg.
Set Target Intensity
Choose your target power zone or enter a custom power percentage.
View Results
See your estimated time along with speed, power, and segment analysis.
Frequently Asked Questions
The calculator uses Zwift's physics model including gradient effects, rolling resistance (Crr = 0.004), and aerodynamic drag. Estimates are typically within 5-10% of actual times, though individual performance varies based on pacing and fatigue.
For short segments (under 5 minutes), you can typically sustain 110-120% of FTP. For medium efforts (5-20 minutes), aim for 100-105% of FTP. For long climbs like the Alpe, sustainable power is usually 85-95% of FTP.
Segment times are calculated for solo efforts without drafting. In a group, you may be slightly faster on flat sections, but climbing times are minimally affected by drafting since air resistance is less significant at climbing speeds.
Differences can occur due to: inconsistent pacing, fatigue from earlier riding, different in-game equipment, use of power-ups, or starting the segment with varying momentum.
Benchmarks are calculated using the segment's actual gradient profile at various W/kg levels. They represent steady-state efforts typical for trained cyclists at each fitness level.
How accurate are the segment time estimates?
What power should I target for a segment PR?
Does drafting affect segment times?
Why do my actual times differ from estimates?
What are the benchmark times based on?
Related Segments
Other climbs in London