Calculate the gear ratio between two gears by entering the number of teeth on the driving and driven gears. Instantly determine whether the setup increases torque or speed, making it ideal for cars, motorcycles, bicycles, RC vehicles, and engineering projects.
✔ Instant calculation • ✔ Cars & motorcycles • ✔ Final drive ratios • ✔ Engineering & motorsport
The gear ratio tells you how many times the driving gear must rotate to turn the driven gear once.
A gear ratio compares the number of teeth on two meshing gears. It determines how rotational speed and torque are transferred between shafts. Lower gear ratios generally provide higher speed, while higher gear ratios increase torque and pulling power.
The gear ratio is calculated by dividing the number of teeth on the driven gear by the number of teeth on the driving gear.
Gear Ratio = Driven Gear Teeth ÷ Driving Gear Teeth
Driving gear:
18 teeth
Driven gear:
54 teeth
Result:
3.00 : 1
Driving gear:
16 teeth
Driven gear:
48 teeth
Result:
3.00 : 1
| Gear Ratio | Effect |
|---|---|
| Below 2:1 | Higher top speed, lower acceleration |
| 2:1 – 3:1 | Balanced performance |
| 3:1 – 4:1 | Strong acceleration and pulling power |
| Above 4:1 | Maximum torque, reduced top speed |
Usually no. A higher numerical gear ratio increases torque but reduces the rotational speed of the driven gear. Lower numerical ratios generally produce higher vehicle speeds.
Manufacturers select gear ratios to balance acceleration, fuel economy, top speed, and engine characteristics. Performance cars often use shorter lower gears for faster acceleration while maintaining taller upper gears for cruising.
This calculator determines the ratio between two gears only. Transmission gear ratios and differential (final drive) ratios can be combined to calculate the overall drive ratio.
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Last Updated: August 2026