Frequency Converter
Convert between hertz, kilohertz, megahertz, gigahertz, and RPM.
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How to use this calculator
- 1
Enter the frequency value you want to convert.
- 2
Select the unit you are converting from (e.g. MHz).
- 3
Select the target unit (e.g. GHz).
- 4
The result appears instantly.
Frequently asked questions
What does this converter handle: frequency only, or wavelength too?
Despite the page’s name it converts frequency units only: hertz, kilohertz, megahertz, gigahertz, RPM and RPS. It does not output wavelengths. To get one, divide the speed of light, 299,792,458 m/s, by the frequency in hertz; that gives the vacuum wavelength in metres.
How is the hertz defined?
One hertz is one cycle per second, so 1 Hz = 1 s⁻¹. The prefixes are decimal: 1 kHz = 1,000 Hz, 1 MHz = 1,000,000 Hz and 1 GHz = 1,000,000,000 Hz. A 3.5 GHz clock therefore ticks 3,500,000,000 times per second.
How do I convert RPM to hertz?
Divide by 60. A hard disk at 7,200 RPM spins at 120 Hz and a 3,600 RPM motor at 60 Hz. In reverse, multiply hertz by 60: 50 Hz is 3,000 RPM. The tool does the same through the factor 1/60.
Is RPS the same as hertz here?
Numerically yes: 1 RPS equals 1 Hz, and 6,000 RPM is 100 RPS. The unit RPS counts revolutions rather than generic cycles, but for rotating equipment the two values agree.
Does mains frequency relate to motor speed?
For a two-pole synchronous machine the shaft turns once per mains cycle, so 50 Hz gives 3,000 RPM and 60 Hz gives 3,600 RPM. Induction motors run a little slower than that, and machines with more poles run proportionally slower, so treat the figure as an upper limit.
Why do my megahertz and gigahertz values not round perfectly?
The tool converts through hertz and shows about ten significant digits, so 2.4 GHz gives exactly 2,400 MHz while a measured value like 33.33 RPM shows 0.5555 Hz. Non-terminating results such as 100 RPM = 1.666666667 Hz are rounded for display.
Can it convert audio pitch or musical notes?
It only changes units of the number you type. It does not map frequencies to note names, and it does not translate between frequency and period; the period is simply 1 divided by the frequency in hertz.
Frequency unit conversion: hertz, megahertz, gigahertz and RPM
Cycles per second and revolutions per minute
Frequency counts how often something repeats. The SI unit is the hertz, one cycle per second, and the prefixed forms step by factors of 1,000. Rotating machinery adds RPM and RPS, which count turns per minute or per second. Because a minute holds 60 seconds, the RPM-to-hertz ratio is a clean division by 60.
Rotation speeds expressed in hertz
Spindle and motor speeds are easier to compare once they share a unit. The table converts typical rotational speeds with the tool.
| RPM | Hertz |
|---|---|
| 500 | 8.333333333 |
| 1,800 | 30 |
| 3,600 | 60 |
| 5,400 | 90 |
| 7,200 | 120 |
Worked examples: radio bands and spinning parts
A 2.4 GHz wireless band is 2,400 MHz, a 5 GHz band is 5,000 MHz, and a 3.5 GHz processor clock is 3,500,000,000 Hz. The 13.56 MHz RFID frequency works out to 13,560 kHz, and 1 GHz equals 1,000,000 kHz. Stepping down is a multiplication by 1,000 per prefix. A 60 Hz mains supply corresponds to 3,600 RPM, and 50 Hz to 3,000 RPM. A drive turning 7,200 times a minute passes its start position 120 times per second, which is also 120 Hz. Dividing by 60 or multiplying by 60 is all the tool is doing.
Frequency and wavelength
Wavelength and frequency are linked by the speed of light, 299,792,458 m/s exactly: the wavelength in a vacuum equals that speed divided by the frequency in hertz. Higher frequency means a shorter wavelength. Use the converter to put the frequency in hertz first, then apply the division with your own calculator.
Choosing the right prefix
Prefixes keep numbers readable: write 2.4 GHz rather than 2,400,000,000 Hz, and 440 Hz rather than 0.44 kHz. Audio work tends to sit in hertz and kilohertz, radio in kilohertz to gigahertz, and mechanical equipment in RPM. When you compare equipment from different fields, convert everything to hertz first. Be careful with RPM: it counts whole turns, so a four-bladed fan at 1,200 RPM turns 20 times per second, but each blade passes a point 80 times per second.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →