Revolutions Per Minute to Kilohertz (rpm to kHz)

1 revolution per minute equals 0.00001666666667 kilohertz (rounded).

How to convert revolutions per minute to kilohertz

To convert revolutions per minute to kilohertz, multiply the number of revolutions per minute by 0.00001666666667. The factor is rounded to 10 significant digits. To go the other way, multiply kilohertz by 60,000.

kilohertz = revolutions per minute × 0.00001666666667

Example: 10 revolutions per minute = 0.0001666666667 kilohertz.

About these units

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

Kilohertz (kHz)

Metric (SI)Current unit

1,000 hertz. AM radio stations are tuned in kilohertz and audio is sampled at 44.1 kHz.

Older radio operators called it the kilocycle. Before the CGPM adopted the hertz in 1960, thousands of cycles per second were written kc/s, and the popular press only switched to kilohertz in the late 1960s. The name changed, but the number on the dial did not.

A kilohertz is 1,000 hertz, a range that covers audible sound and medium-wave radio. Medium wave runs from 531 to 1602 kHz in Europe, Asia and Africa with 9 kHz channel spacing, and from 530 to 1700 kHz in the Americas with 10 kHz spacing. Audio engineers use it for sampling rates: 44.1 kHz comes from the Compact Disc, which Sony used from 1979, and the rate was originally chosen so digital audio could fit on video tape for both PAL and NTSC. Because sampling must exceed twice the highest frequency, 44.1 kHz comfortably covers hearing up to 20 kHz.

1 kilohertz = 1,000 hertz (exactly).

Sources: Wikipedia: Medium wave; Wikipedia: 44,100 Hz; Wikipedia: Kilohertz

Related conversions

See all frequency units.