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Speed to RPM Calculator

Convert speeds such as feet per minute to RPM and vice-versa.

An easy way to convert speed to RPM and RPM to speed


To obtain the speed at which a disk is spinning on a shaft, its diameter and RPM (revolutions per minute) are needed. The formula is as follows:

Speed = RPM x π x Diameter

If we had an RPM of 1200 and a diameter of 1 foot, the speed would be 3769.91 feet per minute. Had the diameter been 12 centimeters instead, the resulting speed would have been 45238.93 centimeters per minute.

To obtain the RPM, the speed of the disk in minutes and its diameter is required. The speed and diameter must be of the same unit type. The formula is as follows:

RPM = Speed ÷ (π x Diameter)

When a radius is provided, it is to be multiplied by 2 to obtain the diameter.

Disk measurement



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