Hertz to Kilohertz (Hz to kHz)

1 hertz equals 0.001 kilohertz exactly.

How to convert hertz to kilohertz

To convert hertz to kilohertz, multiply the number of hertz by 0.001. This factor is exact. To go the other way, multiply kilohertz by 1,000.

kilohertz = hertz × 0.001

Example: 10 hertz = 0.01 kilohertz.

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

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.