Gear Ratio Calculator
Work out gear ratios from the number of teeth on each gear.
How gears trade speed for force
A gear ratio compares the teeth on two meshing gears and tells you how they trade speed against turning force. This works out the ratio from the tooth counts, the fundamental calculation behind bicycles, cars, clocks and any geared machine.
Enter the teeth on each gear to see the ratio.
The universal trade-off
Gears embody one of mechanics' central bargains: you can have speed or force, but not both at once from the same power. A ratio that turns the output faster than the input gives less force, and one that turns it slower gives more — which is why a bike's low gear climbs a hill with easy pedalling but little speed, and a high gear flies on the flat but is brutal uphill. The same principle drives a car's gearbox and a clock's hands moving at different rates.
Gear Ratio Calculator FAQ
What does a gear ratio tell me?
How two gears trade speed against force — a ratio that speeds up the output reduces its force, and one that slows it increases force.
Why does a bike have low and high gears?
A low gear gives more force for climbing at the cost of speed; a high gear gives speed on the flat at the cost of easy pedalling.
Is anything uploaded?
No. The calculation happens in your browser.