Gear Ratio Calculator
Output speed and torque from gear tooth counts.
Enter your values
ⓘ Live results
Results
- Gear ratio
- 3:1
- Output speed
- 600 RPM
- Output torque
- 30 N·m
Quick answer
Gear ratio = driven teeth / driver teeth; output speed = input speed / ratio.
ratio = T_driven / T_driver
How to use the Gear Ratio Calculator
- 1Enter the number of teeth on the driver and driven gears.
- 2Enter the input speed and torque.
- 3Read the gear ratio, output speed and output torque.
Worked example
Using the values the calculator loads with:
Inputs
- Driver gear teeth20
- Driven gear teeth60
- Input speed1800 RPM
- Input torque10 N·m
Results
- Gear ratio3:1
- Output speed600 RPM
- Output torque30 N·m
Frequently asked questions
Does gear ratio change power?
No, ideal gears trade speed for torque but keep power roughly constant, minus small friction losses.
What is a reduction gear?
When the driven gear has more teeth than the driver, output speed drops and torque increases.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.