RPM calculator

Use our RPM Calculator to estimate your engine’s revolutions per minute (RPM) based on your vehicle’s speed, tire diameter, rear gear ratio, and transmission gear ratio.

Please note: this calculator does not factor in drivetrain loss, road conditions, or driver skill.

Engine RPM (revolutions per minute) measures how many times the crankshaft completes a full rotation every minute. With the correct tire size, axle ratio, and final gear ratio, you can easily determine your engine RPM at any given speed — and fine-tune your setup when changing tire sizes or ring and pinion gears to maintain ideal highway RPM.