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RPM Calculator
Calculate revolutions per minute from speed and diameter, or from gear ratio and input RPM.
Speed & Diameter to RPM
RPM
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rad/s
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Gear Ratio to Output RPM
Output RPM
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How this was calculated
Speed to RPM: RPM = (Speed × 63,360) / (π × Diameter × 60) where speed is in mph and diameter in inches.
Gear Ratio: Output RPM = Input RPM / Gear Ratio
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RPM (revolutions per minute) measures rotational speed. Converting between linear speed and RPM requires knowing the wheel or shaft diameter. Gear ratios multiply or divide RPM between connected shafts. Used in pump sizing, motor selection, and drilling operations. Built by Groundwork Analytics.