hertz (Hz)
SI derived unit of frequency. One cycle per second.
The hertz (Hz) is the SI unit of frequency, defined as one cycle per second. It is named after Heinrich Hertz. Swedish mains power runs at 50 Hz, which is 50 cycles every second.
Convert Frequency
Here you can convert units like terahertz, gigahertz, megahertz, kilohertz, etc. within the frequency category.
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Common frequency conversion mistakes
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Revolutions per minute convert to hertz by dividing by 60, not by 1000. The prefix step between hertz and kilohertz is 1000, but the step from minute to second is 60, and the two are easy to mix up.
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Revolutions per second and hertz give the same number but describe different things: rps a rotating object, hertz a periodic signal. Rewriting one as the other never changes the figure.
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A 50 Hz or 60 Hz supply frequency applies to the voltage, not to motor speed in general. Only synchronous motors follow it exactly. An induction motor runs a few percent below it, which is its whole operating principle.
Quick conversion quiz
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25 hertz equals 3.75e+4 millihertz.
Correct answer: 25 hertz = 2.5e+4 millihertz.
14 gigahertz equals 0.014 terahertz.
Correct answer: 14 gigahertz = 0.014 terahertz.
234 gigahertz equals 1.4e+5 megahertz.
Correct answer: 234 gigahertz = 2.34e+5 megahertz.
23 gigahertz equals 2.3e+4 megahertz.
Correct answer: 23 gigahertz = 2.3e+4 megahertz.
209 hertz equals 0.314 kilohertz.
Correct answer: 209 hertz = 0.209 kilohertz.
Definitions
revolution per second (rps)
One revolution per second. Numerically equal to one hertz.
A revolution per second (rps) is one full turn every second. One revolution per second equals exactly 1 hertz, so the number never changes between the two units, only the name of what is being counted.
revolution per minute (rpm)
One revolution per minute. Exactly 1/60 hertz.
A revolution per minute (rpm) is one full turn every minute, which is exactly one sixtieth of a hertz. To convert rpm to hertz, divide by 60: an engine at 3000 rpm turns at 50 Hz.
Frequently asked questions
How do I convert rpm to hertz?
Divide by 60. 3000 rpm is 50 hertz, 1500 rpm is 25 hertz. Multiply by 60 to go the other way.
Why does a motor run at 3000 rpm on a 50 Hz supply?
A two-pole synchronous motor follows the supply frequency exactly: 50 cycles per second becomes 50 revolutions per second, that is 3000 rpm. A four-pole motor runs at half that, 1500 rpm.
Is a revolution per second the same as a hertz?
The number is the same: 1 revolution per second is exactly 1 hertz. Only the name of what is being counted differs, a full turn against a full cycle.
How many megahertz are in a gigahertz?
1000. Every prefix step in frequency is a factor of 1000, so 2.4 GHz is 2400 MHz and 2,400,000 kHz.
How are frequency and period related?
They are inverses. 1 kHz corresponds to a period of 1 millisecond and 1 MHz to a period of 1 microsecond. The period itself converts in the time converter.
How do I use the frequency converter on konvertera.nu?
Enter your frequency (like Hz), choose the target unit (like rpm), and the converter calculates the equivalent value.