Health & Fitness
Bike Gear Ratio, Cadence & Speed Calculator
Updated Aug 27, 2026 Reviewed Aug 27, 2026
Compare chainring and sprocket combinations, rollout, gear inches, speed at cadence, required cadence, total range, and near-duplicate gears.
Drivetrain geometry comparison
Enter gears, wheel rollout and riding input
Result
Calculation summary
Enter values to see the result
Your result, breakdown, assumptions, and warnings will appear here.
Live drivetrain preview
Crank revolutions become wheel travel
Speed = circumference × gear ratio × cadence
- Selected ratio
- 2.941
- Travel per revolution
- 6.28 m
- Speed
- 33.9 km/h
How to use this calculator
- 1Choose speed from cadence or cadence from target speed.
- 2Enter chainrings and sprockets and select one active combination.
- 3Choose a tire preset or measured circumference and review every combination.
Formula
development = wheel circumference × chainring teeth ÷ sprocket teeth
Speed multiplies development by cadence; gear inches use effective diameter and the same ratio.
Calculation steps
- Form every front and rear gear combination.
- Calculate ratio, rollout, gear inches, speed and required cadence.
- Sort rollout values to identify range and near-duplicates.
Worked example
A 2.136 m wheel with 50×17 gearing travels about 6.28 m per revolution and reaches about 33.9 km/h at 90 rpm.
Assumptions
- The tire rolls without slip.
- Preset circumferences are nominal.
- Measured rollout is normally more accurate.
- Efficiency and component compatibility are excluded.
Sources
Frequently asked questions
Should I use measured circumference?
Yes when accuracy matters; presets are nominal starting points.
What is development?
It is ground distance travelled for one crank revolution.
What are gear inches?
Effective wheel diameter in inches multiplied by tooth ratio.
What counts as overlap?
Adjacent sorted rollout values within 1.5% are counted as near-duplicates.
Related calculators
Cycling FTP & Power Zones Calculator
Enter a known FTP or estimate it from a field test, then calculate seven cycling power zones, sweet spot power, and watts per kilogram.
Cycling Power, Grade & Speed Calculator
Estimate steady cycling speed from power or required power from speed using grade, mass, distance, wind, rolling resistance, aerodynamics, and drivetrain loss.