What Does Megahertz Mean?

Megahertz (MHz) is a frequency unit of cycles per second that measures transmissions through airwaves or conduits, such as network cable or fiber optic cable. A Hertz (Hz) is one cycle per second. One MHz equals one million (1,000,000) Hz.


MHz is a common measure of the transmission speed of electronic devices, such as computer buses, RAM and CPUs. MHz refers to the CPU master clock signal or speed frequency used to measure CPU models between 1974 and 2000. However, most modern CPUs measure clock speed in gigahertz (GHz) (109 Hertz), with typical clock speeds ranging from 1 to 4 GHz or higher.

Techopedia Explains Megahertz

One MHz has a one-nanosecond frequency cycle. A nanosecond is one-thousandth of a microsecond, which is one-billionth of a second.

Hertz represents total rotations or cycles per second. Stated differently, one cycle per second equals one Hz.

Clock speed is also measured in Hz and refers to the synchronous circuit clock frequency of CPUs. One clock lasts only one nanosecond and toggles between 0 and 1. Modern and non-embedded CPUs may have a single clock cycle of less than one nanosecond.

Clock rate is measured by a crystal oscillator, which generates highly accurate and unwavering electrical and clock signals. The oscillator circuit brings its crystal a small amount of electricity every nanosecond, which is also measured in Hz.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.