How accurate are the time estimates?
The estimates are based on a physics model using your FTP, weight, height, target power zone, and route elevation. They are accurate to within roughly 5–15% for most riders. Real-world times can vary due to in-game events, pacing strategy, drafting dynamics, and the specific Zwift bike and wheels you use. See also our Bike Speed Calculator.
What power zone should I choose?
Zone 2 (Endurance, ~65% FTP) is ideal for long base rides. Zone 3 (Tempo, ~80% FTP) suits most standard Zwift group rides and events. Zone 4 (Threshold, ~93% FTP) reflects a hard race-pace effort. Pick the zone that best matches how you plan to ride the route.
How does the draft calculation work?
In Zwift, riding in a group significantly reduces aerodynamic drag. The draft percentage slider estimates how much of that drag saving you'll benefit from — 0% means solo with full drag, while values of 25–40% are typical for a mid-group ride. Higher draft percentages will increase your estimated average speed and reduce completion time.
Does the calculator account for Zwift bike and wheel bonuses?
No, the calculator uses a baseline aerodynamic and rolling resistance model. Certain high-end Zwift bike and wheel combinations can provide meaningful speed bonuses — particularly on flat routes. If you're using a top-tier setup, your actual times may be a few percent faster than the estimate. You might also find our calculate Number of Links Required, Chain Length & Chain Length (cm) — Chain Length useful.
Why do my actual times differ from the estimates?
Several factors affect real ride times that aren't captured here: how consistently you hold your target power, your exact in-game weight and height settings, the specific route's terrain profile versus a simple average gradient, rubber-banding in group rides, and any stops or power drops mid-ride. Use the estimate as a planning guide rather than a precise prediction.
What is TSS and why does it matter?
Training Stress Score (TSS) quantifies the overall training load of a ride based on duration and intensity relative to your FTP. A TSS of 100 roughly equals one hour at threshold power. Tracking TSS helps you manage fatigue, plan recovery, and build fitness progressively over time.
What is FTP and how do I find mine?
FTP (Functional Threshold Power) is the maximum average power you can sustain for approximately one hour. In Zwift, you can estimate it by performing the built-in FTP Test or a Ramp Test. A typical recreational cyclist falls between 150–250W, while trained riders often exceed 300W.
How does elevation affect my estimated time?
Higher elevation gain slows your average speed significantly because climbing requires more power for less forward progress. The calculator applies a gradient-based speed adjustment — routes with steep climbing (like Alpe du Zwift or mountain portals) will show considerably longer times than flat routes of the same distance.