About the Frequency Converter
This converter changes a frequency between millihertz, hertz, kilohertz, megahertz, gigahertz, terahertz, radians per second and revolutions per minute. Type a value, choose the unit you have and the unit you want, and the answer appears at once together with the same frequency in every other unit. Below the list you also get the time for one cycle (the period) and the wavelength of a wave travelling at the speed of light, which suits radio, Wi-Fi and light. Wavelength here assumes travel in a vacuum; in cable, glass or water a wave is slower and shorter, and sound travels far slower than light, so do not use the wavelength line for sound. Numbers are shown to eight significant digits and very large or small values switch to scientific notation.
Updated September 2026
How to use the Frequency Converter
- 1Type the frequency in the Value box. Decimals and commas such as 2.4 or 1,500 are fine.
- 2Pick the unit you have in From and the unit you want in To, or press a common frequency such as FM radio to fill both the value and the unit.
- 3Read the big answer, or scan the list for every other unit at once.
- 4Check the period and wavelength lines when you need the length of one cycle or the size of a radio wave.
- 5Press Copy result to take the plain number without thousands commas, or use the swap button to reverse the direction.
Reading frequency units
A frequency counts how many times something repeats each second. One hertz is one repeat per second, and the other units add a prefix: kilo means a thousand, mega a million, giga a billion and tera a trillion. Mains electricity is 50 or 60 Hz, music notes sit in the hundreds of hertz, FM radio in the tens of megahertz, phones and Wi-Fi in gigahertz, and visible light in hundreds of terahertz.
Processor speeds and radio channels are printed in megahertz or gigahertz, while sound and power are usually in hertz. A quick swap between them is just moving the decimal point by three, six or nine places, which this tool does for you without slips.
Hertz, radians per second and rpm
Rotating machines are usually rated in revolutions per minute, while electrical and physics formulas use hertz or radians per second. The link is simple: one revolution per second is one hertz, and one hertz is 2π radians per second.
- rpm to Hz: divide by 60
- Hz to rad/s: multiply by 2π (about 6.2832)
- rad/s to Hz: divide by 2π
- A four-pole motor on 50 Hz mains turns at about 1,500 rpm
Period and wavelength
Two useful numbers come from any frequency. The period is the time one cycle takes and is the inverse of the frequency. The wavelength is the distance a wave travels in one cycle, found by dividing its speed by the frequency. Higher frequency means a shorter cycle and a shorter wave.
Antenna designers use this to pick lengths: a quarter wave at 100 MHz is roughly 75 centimetres. Remember that the wavelength on this page is for light or radio in a vacuum. Through a coaxial cable a signal travels at about two thirds of that speed, and sound in air moves at about 343 metres per second, so work those cases out with their own speed.
Phone and computer tips
Tap a common frequency chip to load a real example, then change the units to see how the numbers shift. Results round to eight significant digits, so a slight difference in the last place is rounding, not an error. Frequency often sits next to other physics units. Turn angles into turns with the Angle Converter, move between joules and calories with the Energy Converter, change watts into horsepower with the Power Converter, and use the Unit Converter for everything else.
Features
- Eight frequency units in one list
- Every unit shown at once under the main answer
- Period (time for one cycle) in seconds, milliseconds, microseconds or nanoseconds
- Wavelength in a vacuum, in metres, centimetres or millimetres
- One-press examples: mains, concert pitch, FM radio, Wi-Fi and visible light
- Swap button for reversing the units
- Scientific notation for extreme values, never NaN
- Runs in your browser, nothing is uploaded
Frequently asked questions
How many hertz are in a megahertz?
One megahertz is 1,000,000 hertz, or 1,000 kilohertz. So 100 MHz, a typical FM radio station, is 100,000,000 Hz. Type 100, choose megahertz as the starting unit and hertz as the target to see it.
How do I convert hertz to radians per second?
Multiply the frequency in hertz by 2π, about 6.2832. One hertz is 6.283185 rad/s, and 50 Hz mains power is about 314.16 rad/s. Engineers call this the angular frequency and write it as ω.
How do I convert rpm to hertz?
Divide the revolutions per minute by 60. A motor at 3,000 rpm turns 50 times a second, which is 50 Hz, and 60 rpm is exactly 1 Hz. To go from hertz back to rpm, multiply by 60.
What is the period of a frequency?
The period is how long one full cycle lasts, which is 1 divided by the frequency. At 50 Hz one cycle takes 0.02 seconds (20 ms). At 2.4 GHz it is only about 0.42 nanoseconds. The tool shows it beside every result.
How do I find the wavelength from a frequency?
Divide the speed of the wave by the frequency. For radio and light in a vacuum the speed is 299,792,458 metres per second, so 100 MHz has a wavelength of about 3 metres. The page uses that speed, so it is not meant for sound or for waves inside a cable.
What is the difference between MHz and mHz?
A capital M means mega, a million, while a small m means milli, a thousandth. So 1 MHz is one million hertz but 1 mHz is one thousandth of a hertz. The two differ by a factor of a billion, which is why the list spells out the names.