Free cycling tools · your starting point
How fast can you ride at your power?
Your effort
Your body
Your bike and route
- Example estimate · Estimated speed
- 33.6km/h
Speed
Estimated speed: 33.6 km/h.
Where does your power go?
- Climbing
- 0 W
- Rolling resistance
- 35.5 W
- Air resistance
- 164.6 W
- Total system weight
- 83.5kg
- Speed
- 33.6km/h
Adjust in this order
- Check your weight, bike and surface.
- Compare the same route at different power levels.
- Test your pace outside; wind and changing terrain matter.
Does your gearing suit the climb?
Compare your chainrings and cassette before setting off.
Check your gearingFree account
Make this advice more personal
Save your FTP and weight once; every climbing and gearing calculation uses them.
- Your details stay saved. No need to enter them again, even in other calculators.
- A narrower range. Your own weight and FTP make it easier to compare calculations.
- Your next step is ready. Take your details to the climb planner, gearing calculator or nutrition calculator.
These details go with you to your account
Nothing entered yet. Move a slider or choose an option; only what you enter goes with you.
Save my details · free accountYour entered values go with you; there is no need to enter them again. No account? Your result above stays available.
Your entered details are only remembered for this browser session.
The short answer
Power alone does not determine speed. Your weight, bike, surface and gradient also matter. The calculator estimates speed at your power, or the power required for a chosen speed.
How we calculate
The model adds aerodynamic, rolling and climbing resistance. It then finds the speed at which your input power matches that resistance. Bike type and surface set the fixed model assumptions.
What this cannot tell you
This calculation assumes steady conditions. Wind, corners, traffic and your actual position can change your speed. The estimate is not a promise for your next ride.
Worked example
An example with fixed inputs. Use the calculator for your own details.
Input
- Rider weight
- 75 kg
- Bike weight
- 8.5 kg
- Bike
- Road bike, asphalt
- Gradient
- 0 %
- Power
- 200 W
Calculated result
- Speed
- 33.62 km/h
Common mistakes
- Entering rider weight but forgetting bike weight.
- Comparing a brief power peak with average speed over an entire ride.
- Using asphalt settings for a gravel route.
What this tool is for
Translate watts into course reality
Speed is shaped by more than power. This page keeps gradient, drag, and rider context visible so the result stays useful rather than falsely precise.
Context over shortcuts
A raw watt number does not tell you enough. Course profile, wind, and position change the answer in real riding conditions.
Keep uncertainty visible
The estimator is best treated as a range and a conversation starter, not a substitute for testing or race experience.
Useful for pacing decisions
Once speed expectations are clearer, it becomes easier to plan climbs, time trials, and long steady efforts with fewer surprises.
Common problems riders try to solve
Estimating whether a target power actually translates into the speed they expect.
Comparing efforts on flat and hilly terrain without adjusting for drag and gradient.
Setting pacing goals without understanding how much position and route shape the outcome.
What to check first
Check the course profile before trusting a speed estimate.
Make sure the power input reflects the effort you can actually hold for the event length.
Use the result as a pace guide, not as a guarantee of finish time.
What not to change blindly
Do not assume a small watt increase always produces the same speed gain everywhere.
Do not ignore aerodynamics and rolling resistance when comparing outputs.
Do not treat a single speed estimate as a substitute for race-specific testing.
FAQ
FAQ
Why is speed harder to estimate than power?
Because speed is affected by gradient, wind, surface, position, and mass as well as power.
Can this be used for time trial pacing?
Yes, as a first-pass reference. For a serious event plan, use the dashboard and real course testing as the next step.
Explore more
Related guides
Keep going with related guides and calculators that build on what you just learned.