Rod Ratio Calculator

Enter the length of your piston rod under Rod Length and the stroke length of your engine crankshaft under Stroke and press solve to find the rod ratio for your vehicle.

RANDYS Worldwide makes no guarantee to the accuracy of calculations. Please email with any calculation errors.

Rod ratio is the mathematical relationship of the length of the connecting rods and the stroke rating of the crankshaft. This calculator divides the overall rod length by the stroke, in inches, to generate a ratio. Rod ratio is a hornet’s nest of controversy. It’s a single variable in the complicated equation that is performance engine building. This calculator will give you the ratio, how you distill the long stroke versus short stroke conundrum is up to you.