Ride speed · gear ratio · adjustments
Bicycle Speed Calculator
Use miles, mph, and pounds by default, or switch to metric when your ride log is in kilometres. Gear ratio, cadence, gradient, wind, and surface adjustments stay on the same screen.
Conditions
Choose the value you want to solve, then enter the other two values.
Results
The main speed and ride time update as soon as the inputs change.
Gear and cadence
Fill the optional bike setup to calculate development and theoretical speed.
Ride adjustment
Gradient, wind, and surface are planning estimates, not a replacement for ride data.
Cycling speed guide
Bicycle Speed Calculator
Use the calculator when you want one screen for average speed, gear development, cadence speed, and rough ride-condition adjustments. The English page defaults to miles, mph, and pounds because many English-language ride logs—especially US-focused ones—use imperial units, while a metric switch remains available for kilometre-based training plans.
Start with the value you need
- Pick speed, time, or distance first. The hidden field is the result you are asking for.
- Enter the two known values. In the default imperial view, 50 mi and 2 h gives 25 mph. Switch to metric when your ride is logged in kilometres.
- Use the gear panel only when you want to compare chainring, sprocket, wheel size, and cadence.
- Leave gradient, wind, and surface at the default values when you only need the basic average.
What the calculator does behind the screen
- Average speed is distance divided by time; time is distance divided by speed; distance is speed multiplied by time.
- Gear development is gear ratio multiplied by wheel circumference. Cadence speed is RPM multiplied by development and converted to km/h.
- Calories use a speed-based MET estimate. Power uses a simplified resistance model with rider weight, bike mass, gradient, wind, and surface coefficient.
A realistic reading
- 50 mi in 2 h returns 25 mph and a pace near 2 min 24 s per mile.
- A 50T / 12T setup on a 700C wheel at 90 RPM gives about 29.3 mph as cadence speed.
- With 154 lb, a 3% gradient, concrete, and an 8 mph headwind, the adjusted speed is about 18.2 mph. The power estimate stays in watts.
Use the adjustment as a planning estimate
- Gradient, wind, road surface, body position, tyres, drafting, and bike maintenance can move the real speed a lot.
- Do not operate the calculator while riding. Stop first, then compare the result with your ride computer or training log.
FAQ
Do I need body weight for the basic speed result?
No. Body weight is only used for calorie and power estimates. Speed, time, distance, gear ratio, development, and cadence speed can be calculated without it.
Why does the English page default to miles?
Because many English-language ride notes, especially US-focused ones, use miles, mph, and pounds. If your training plan or cycling computer is set to kilometres, use the metric option before entering values.
How should I choose tailwind or headwind?
Choose tailwind when the wind pushes from behind in your riding direction, and headwind when it meets you from the front. If the wind is mostly sideways or unclear, use None.
Why can the result differ from my ride computer?
The calculator uses a simplified model. Rider position, tyres, pressure, road surface, wind angle, fatigue, and sensor calibration can all change the real-world record.