Gear Ratio Calculator
Ratio, output speed and torque.
Reviewed by James Whitfield · How we check our maths
Your values
ⓘ Live results
Results
- Gear ratio
- 3:1
- Output speed
- 583 rpm
- Output torque
- 36 Nm
- Mechanical advantage
- 3
Quick answer
Gear ratio is driven teeth divided by driving teeth; it trades speed for torque.
The formula
Ratio = driven teeth ÷ driving teeth
Worked example
Worked example
Using the values the calculator loads with.
Inputs
- Driving gear teeth18
- Driven gear teeth54
- Input speed1750 rpm
- Input torque12 Nm
Result
- Gear ratio3:1
- Output speed583 rpm
- Output torque36 Nm
- Mechanical advantage3
How to use the Gear Ratio Calculator
- 1Enter the tooth count of both gears.
- 2Enter input speed and torque.
- 3Read the output speed and torque.
Frequently asked questions
Does a gearbox create power?
No — torque rises only as speed falls, minus friction losses.
What is overdrive?
A ratio below 1:1, which raises speed and reduces torque.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error