Why use this calculator
Gear ratio calculations are fundamental to mechanical engineering, automotive design, robotics, and any system involving power transmission.
How to use it
Enter the number of teeth on the driving and driven gears, along with input speed and torque. The calculator shows the resulting ratio, output speed, and torque.
The formula
Gear Ratio = Driven Teeth / Driving Teeth. Output RPM = Input RPM / Ratio. Output Torque = Input Torque × Ratio.
Worked examples
20-tooth driving gear, 60-tooth driven gear, 1000 RPM input
3:1 ratio, 333 RPM output, 3x torque multiplication
When people use it
- Mechanical design
- Automotive engineering
- Robotics
- Industrial machinery
Tips
- Higher ratios reduce speed but increase torque
- Multi-stage gearing multiplies individual ratios
- Account for friction losses in real systems (typically 1-3% per stage)
Questions people ask
- What is a gear ratio?
- A gear ratio describes the relationship between the speeds and torques of connected gears. A 3:1 ratio means the output turns 3 times slower but with 3 times more torque than the input.