Hertz to Revolutions Per Minute (Hz to rpm)

1 hertz equals 60 revolutions per minute exactly.

How to convert hertz to revolutions per minute

To convert hertz to revolutions per minute, multiply the number of hertz by 60. This factor is exact. To go the other way, multiply revolutions per minute by 0.01666666667 (rounded).

revolutions per minute = hertz × 60

Example: 10 hertz = 600 revolutions per minute.

About these units

Hertz (Hz)

Metric (SI)Current unit

The SI unit of frequency: one cycle per second. Named after Heinrich Hertz.

Heinrich Rudolf Hertz (1857 to 1894) was a German physicist who, in experiments between 1886 and 1889, produced and detected radio waves with a spark-gap transmitter and a loop receiver. He showed that they travel at the speed of light and can be polarised, reflected and refracted, confirming Maxwell's theory. Asked about uses for them, he is said to have replied, Nothing, I guess. The International Electrotechnical Commission established the name hertz in 1935, and the CGPM adopted it in 1960, replacing cycles per second.

One hertz is one cycle per second, equal to s to the minus one. A clock ticking once a second runs at 1 Hz, a human heart at rest beats at around 1.2 Hz, and young ears hear roughly 20 Hz to 20,000 Hz. The SI treats cycle itself as not a unit, and the hertz applies only to periodic events, whereas the becquerel counts random radioactive decays, even though both are one per second. The second is now defined by fixing the caesium frequency at exactly 9,192,631,770 hertz.

The hertz is the reference unit for frequency on this site.

Sources: Wikipedia: Hertz; Wikipedia: Heinrich Hertz; BIPM: SI Brochure, 9th edition

Revolution Per Minute (rpm)

Metric (SI)Current unit

One 60th of a hertz. The unit for engine, motor and turntable speeds.

Records gave rpm its fame. The 78 rpm speed was not chosen for a clear engineering reason; Wikipedia says it apparently happened to be the speed of one of the early machines, and the Gramophone Company formally set it as a recording standard in 1912. Columbia unveiled the 33 and a third rpm LP on 21 June 1948, and RCA Victor released the 45 rpm single in February 1949, starting a period called the War of the Speeds.

One rpm equals one sixtieth of a hertz, so a disc at 60 rpm turns at 1 Hz. The SI does not recognise rpm as a unit, preferring hertz or radians per second, and r/min is the usual symbol in standards. Typical examples are a modern car engine idling at about 750 to 900 rpm, consumer hard drives at 7,500 to 10,000 rpm, power-generation turbines at 3,000 or 3,600 rpm, and uranium centrifuges of the Zippe type at 100,000 rpm or more.

1 revolution per minute = 0.01666666667 hertz (approximately).

Sources: Wikipedia: Revolutions per minute; Wikipedia: Phonograph record

Related conversions

See all frequency units.