Enter the output RPM and the input RPM into the RPM Gear Ratio Calculator. The calculator will evaluate and display the RPM Gear Ratio. 

RPM Gear Ratio Formula

The following formula is used to calculate the RPM Gear Ratio. 

RGR = O / I 
  • Where RGR is the RPM Gear Ratio (output:input)
  • O is the output RPM 
  • I is the input RPM 

To calculate the RPM gear ratio, divide the output RPM by the input RPM.

How to Calculate RPM Gear Ratio?

The following example problems outline how to calculate RPM Gear Ratio.

Example Problem #1:

  1. First, determine the output RPM.
    • The output RPM is given as: 500.
  2. Next, determine the input RPM.
    • The input RPM is provided as: 100.
  3. Finally, calculate the RPM Gear Ratio using the equation above: 

RGR = O / I 

The values given above are inserted into the equation below and the solution is calculated:

RGR = 500 / 100  = 5:1 (output:input)


What is the significance of the RPM Gear Ratio in mechanical systems?

The RPM Gear Ratio is crucial in mechanical systems as it determines the balance between speed and torque. A higher gear ratio can increase torque but reduce speed, making it essential for applications requiring significant force. Conversely, a lower gear ratio increases speed, beneficial for applications needing rapid movement.

How can the RPM Gear Ratio affect the efficiency of a gearbox?

The efficiency of a gearbox is directly influenced by its RPM Gear Ratio. A well-chosen gear ratio can optimize the power transmission, reducing energy losses and improving the overall efficiency of the system. Incorrect gear ratios can lead to increased wear and tear, higher energy consumption, and reduced performance.

Can the RPM Gear Ratio be adjusted after installation?

Adjusting the RPM Gear Ratio after installation is possible but depends on the type of gearbox. Some gearboxes, like those with adjustable pulleys or variable-speed drives, allow for easy adjustments. However, fixed gear ratios in standard gearboxes might require replacing gears or the entire gearbox to change the ratio, which can be more complex and costly.