Cycling / Gearing
Cycling Speed Calculator: Speed and Cadence
Use chainring and cog tooth counts, wheel diameter and tyre width to calculate pedalling speed in km/h or mph, or reverse the calculation for a target speed.
Cycling Speed Calculator: Speed and Cadence: Estimates wheel diameter as bead seat diameter plus twice tyre width. Circumference times the chainring-to-cog ratio gives distance per crank turn. Multiplying by cadence gives speed; dividing target speed by distance per turn gives cadence. Runs 100% locally in your browser with zero server file uploads.
- Category
- Health & sport tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
The starting wheel is 700 × 28c: a 622 mm bead seat diameter and 28 mm tyre width. Speed follows gearing and cadence while pedalling without slip. It does not predict the power needed, wind, gradients or coasting. Actual loaded tyre circumference can differ from this geometric estimate.
Mechanical calculation
Distance per turn in metres = π × wheel diameter in mm ÷ 1000 × chainring teeth ÷ cog teeth. Speed in km/h = distance per turn × rpm × 60 ÷ 1000. Cadence is the inverse of that calculation. The bike gear calculator compares multiple gears.
Tyre dimensions and units
Tyre widths and bead seat diameters follow the ETRTO dimensional convention. Standards-body catalogue: https://www.etrto.org/Publications . One international mile is exactly 1609.344 metres; NIST Guide to the SI, Appendix B: https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors. Both conversion factors are exact.
How to use it
- Choose speed from cadence or cadence for a target speed.
- Enter one chainring and rear cog, wheel bead seat diameter and tyre width.
- Read cadence, speed, distance per turn and estimated wheel circumference.
Privacy & limitations
Gearing and speed are calculated in your browser and are not uploaded or saved.
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Frequently asked questions
How is this different from the bike gear calculator?
The bike gear calculator compares every chainring and cog combination, including gear inches and gain ratio. This page focuses on one gear and adds the reverse question: cadence needed for a chosen speed.
What does 700 × 28c mean here?
The default uses a 622 mm bead seat diameter and a 28 mm tyre width. The 700 label is a nominal size; do not enter 700 as the bead seat diameter.
Will this predict how fast I can ride?
It gives the mechanical speed at a cadence while the wheel turns without slip. It does not model aerodynamic drag, rolling resistance, gradients, power or coasting. Loaded tyre circumference can differ from the estimate.
Free tool · runs in your browser · no account required