📶 Frequency

Frequency Converter

Radio bands in megahertz, CPUs in gigahertz, motors in RPM — convert any cycle rate. Enter the value and press Convert.

Written and reviewed by SM Arijul Islam · Last reviewed · Editorial standards · Report an error

About the frequency converter

Frequency counts repeating events per second and is measured in hertz. In electronics it describes signals and clock speeds; in mechanics it describes rotation, where 1 hertz equals 60 revolutions per minute.

Factors used

  • 1 kHz = 1,000 Hz · 1 MHz = 10⁶ Hz · 1 GHz = 10⁹ Hz
  • 1 THz = 10¹² Hz
  • 1 RPM = 1/60 Hz ≈ 0.016667 Hz
  • 1 beat per minute (BPM) = 1/60 Hz
  • Period (seconds) = 1 ÷ frequency (Hz)
Need the time instead? Try the Time Converter or the Speed Converter.

How to convert frequency

Frequency counts how often a repeating event occurs each second, measured in hertz (Hz). One hertz is one cycle per second, a kilohertz is a thousand cycles, a megahertz a million and a gigahertz a billion. Frequency is the reciprocal of period, so a 50 Hz wave completes a cycle every 20 milliseconds. Converting between frequency and wavelength needs one extra piece of information: the wave's speed.

Common frequency conversions

One megahertz expressed in other units of frequency
Unit1 megahertz equals
Revolutions per minute (RPM)60,000,000
Hertz (Hz)1,000,000
Kilohertz (kHz)1,000
Gigahertz (GHz)0.001
Terahertz (THz)0.000001

Everyday uses

  • Radio, Wi-Fi and mobile bands
  • Processor and memory clock speeds
  • Audio pitch, tuning and hearing ranges
  • Mains electricity and power quality
  • Vibration and machine monitoring

Frequently asked questions

They are reciprocals: frequency = 1 ÷ period. A 60 Hz supply therefore has a period of about 16.67 ms.
It was a historical compromise between transformer size and visible flicker. Europe largely chose 50 Hz and North America 60 Hz.
It describes the processor's clock — roughly how many billion cycles it completes each second.
Yes, with wavelength = speed ÷ frequency. Sound in air travels at about 343 m/s; light at about 299,792,458 m/s.
60 Hz means 60 cycles per second. One cycle is one revolution, so 60 × 60 = 3,600 RPM.

More worked examples

  • One kilohertz is 1,000 Hz, and one gigahertz is 1,000,000,000 Hz.
  • A 50 Hz mains supply completes 50 cycles every second, giving a period of 20 milliseconds.
  • Wi-Fi at 2.4 GHz operates at 2,400,000,000 cycles per second.
  • The note A above middle C, at 440 Hz, has a period of about 2.27 milliseconds.

Quick reference

Common frequency units and the periods they correspond to
FrequencyEquivalent
1 hertz1 cycle per second
1 kilohertz1,000 Hz
1 megahertz1,000,000 Hz
1 gigahertz1,000,000,000 Hz
50 Hz20 millisecond period
60 Hz16.67 millisecond period
60 rpm1 Hz

Common mistakes to avoid

  • Confusing frequency with period. They are reciprocals, so a higher frequency means a shorter period.
  • Assuming revolutions per minute equal hertz. Divide by 60, so 3,000 rpm is 50 Hz.
  • Mixing up kilo and mega when reading specifications, which is a factor of 1,000 between them.
  • Reading a 50 Hz supply as 50 cycles per minute. It is 50 cycles per second, which is 3,000 per minute.

Further questions

One cycle per second, named after Heinrich Hertz. It measures how often a repeating event occurs.
Divide the revolutions per minute by 60, since there are 60 seconds in a minute.
They are inversely proportional: speed equals frequency multiplied by wavelength. For light, higher frequency means shorter wavelength.
Historical infrastructure choices from the early twentieth century. Europe and most of Asia standardised on 50 Hz, while North America uses 60 Hz.

Sources and standards

The hertz is one cycle per second and is an SI derived unit with a special name. NIST SP 811 defines it, and the page separates frequency from angular frequency, where one hertz corresponds to 2π radians per second.

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