What is a gear ratio?

Gear ratio is the number of times the rear wheel turns for each pedal revolution. A 50/17 gear has a ratio of 2.94, meaning the rear wheel turns 2.94 times per pedal turn.

What is a good gear ratio for road cycling?

Typical road setups range from about 1.5 (easy climbing) to 4.5 (fast descending). A 50/17 (2.94) is a good all-round flat riding gear.

How do gear inches relate to gear ratio?

Gear inches = Gear ratio x Wheel diameter (in inches). It represents the equivalent wheel diameter of a directly-driven penny-farthing bicycle. Higher gear inches = harder gear.

Development is the distance the bike travels per pedal revolution. Development (m) = Gear ratio x Wheel circumference (m). A higher development means you travel further per pedal turn.

BikeCalcs

Gear Ratio Calculator — Chainring to Sprocket Ratio

Calculate gear ratios from chainring and sprocket tooth counts.

Chainring Teeth

Sprocket Teeth

Wheel Circumference

700x25c = 2105mm

How We Calculate This

Gear Ratio Formulas

Gear Ratio = Chainring teeth / Sprocket teeth
Gear Inches = Gear Ratio x Wheel diameter (inches)
Development (m) = Gear Ratio x Wheel circumference (m)

Frequently Asked Questions

Related Calculators

Gear Inches Calculator

Convert gear ratios to gear inches for comparison.

Development Calculator

Calculate distance travelled per pedal revolution for any gear.

Chainring Calculator

Compare chainring sizes and their effect on gearing range.

Cassette Calculator

Analyse cassette tooth counts and gear jumps between sprockets.

Speed in Gear Calculator

Calculate road speed for any gear at a given cadence.

Last updated: 2025-02-20

All calculations are estimates. Always verify results and consult a professional bike fitter where appropriate.