Auto & Transport
Gear Ratio Calculator - Calculate speed vs RPM for different gear ratios
Calculate speed vs RPM for different gear ratios
Formulas and edge cases are reviewed against authoritative references before publication. For methodology, editorial standards, or corrections, use the links below.
Frequently asked questions
What is final drive ratio?
The gear ratio in the differential. Higher number = more torque multiplication, lower top speed.
Why calculate this?
Helps choose gearing for desired RPM at cruising speed, or planning transmission swaps.
Does tire size affect this?
Yes, larger tires effectively lower your gearing - higher speed per RPM but less acceleration.
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About this tool
This Gear Ratio Calculator turns your inputs into practical results. Provide Tire Diameter, Final Drive Ratio, and Gear Ratios to calculate Speed at Target RPM and RPM at 60 mph by Gear.
Adjust values to compare scenarios and see how sensitive the result is. The calculation uses the numbers as entered, so double-check units and expect small differences from rounding in the displayed totals.