Automotive Calulators
Front Yard
Data Center North
Solar backup power
Water cooled PC

Gear ratio and speed calculator.

This program will calculate the speed of a vehicle for every gear. If you have a trans-axle use 1 for the rear end ratio.

For those interested this is accomplished by dividing the RPM by the final gear ratio then multiplying the circumference of the tire.

Number of transmission gears


Engine RPM

Rear end gear ratio

Tire diameter

Tire Size Calculator

This calculator will assist you in determining the actual size of your tire. Currently very limited and only usable for passenger car tires.

What Next?

I'm looking for suggestions for something else to work out. Compression ratio or maybe airflow requirements for horsepower any suggestions drop me a note.

Finally the cursory disclaimer. This is for informational purposes only. Results are not guaranteed to be correct.