Rear Gear Ratio Calculator
Solve for any one value: Gear Ratio, Tire Diameter, RPM, Speed, or Transmission Ratio.
How to Use This Calculator
This tool allows you to calculate one of the following based on the other four inputs: Rear End Gear Ratio, Tire Diameter, Engine RPM, Vehicle Speed, or Transmission Gear Ratio.
- Enter values into four out of five input fields.
- Leave exactly one field blank — this is the one the calculator will automatically solve for.
- Press the Calculate button to compute the missing value.
- The result will appear in the field you left blank.
- You can reset any individual input using its Clear button.
Field Descriptions:
- Rear End Gear Ratio: Final drive/differential ratio (e.g., 3.73 or 4.10)
- Tire Diameter: Overall tire height in inches (e.g., 28.0)
- Engine RPM: Engine speed in revolutions per minute
- Vehicle Speed: Speed of the vehicle in miles per hour
- Transmission Gear Ratio: Current gear ratio (e.g., 1.00 for 1:1, 0.70 for overdrive)