Frequency Converter

Frequency is how many times something repeats per unit of time: the cycles of an alternating current, the vibrations of a sound, or the turns of a shaft. Its SI unit is the hertz (Hz), one cycle per second, so 5,000 cycles in one second is a frequency of 5 kHz.

A rotation is a cycle too, so rotational speeds such as revolutions per minute (RPM) and radians per second convert to hertz: one revolution per second is 1 Hz.

How to convert frequency

Type a value into any field, and every other unit is calculated at once. For example, a motor turning at 3,000 RPM:

1. In hertz: divide by 60.

   3,000 / 60 = 50 Hz

2. In radians per second: one turn is 2π radians, so multiply the hertz by 2π.

   50 * 2 * π = 314.2 rad/s

The angular frequency in rad/s is written ω, and ω = 2 * π * f.

Common conversions

Frequency units

• Hertz (Hz): The hertz is the unit of frequency in the International System of Units, equivalent to one cycle per second. The hertz is an SI derived unit whose expression in terms of SI base units is s⁻¹, meaning that one hertz is the reciprocal of one second.
  Conversion Factor: 1 Hz = 1 Hz (Base Unit)

• Kilohertz (kHz): Kilohertz represents one thousand cycles per second.
  Conversion Factor: 1 kHz = 1,000 Hz

• Megahertz (MHz): Megahertz represents one million cycles per second.
  Conversion Factor: 1 MHz = 1,000,000 Hz

• Gigahertz (GHz): Gigahertz represents one billion cycles per second.
  Conversion Factor: 1 GHz = 1,000,000,000 Hz

• Revolutions/Second (rev/s): Revolutions per second represent the number of complete rotations around a fixed axis in one second.
  Conversion Factor: 1 rev/s = 1 Hz

• Revolutions/Minute (rev/min): Revolutions per minute represent the number of complete rotations around a fixed axis in one minute.
  Conversion Factor: 1 rev/min = 1/60 rev/s = 1/60 Hz

• Degrees/Second (°/s): Degrees per second represent the angular displacement in degrees per second.
  Conversion Factor: 1°/s = 1/360 Hz

• Degrees/Minute (°/min): Degrees per minute represent the angular displacement in degrees per minute.
  Conversion Factor: 1 °/min = 1/60 °/s = 1/21600 Hz

• Radians/Second (rad/s): Radians per second represent the angular displacement in radians per second.
  Conversion Factor: 1 rad/s = 1/(2π) Hz = 0.159155 Hz

• Radians/Minute (rad/min): Radians per minute represent the angular displacement in radians per minute.
  Conversion Factor: 1 rad/min = 1/60 rad/s = 0.00265258 Hz

• RPM: RPM is another name for Revolutions Per Minute and represents the number of complete rotations around a fixed axis in one minute.
  Conversion Factor: 1 RPM = 1/60 Hz

Frequently asked questions

How do you convert frequency to time?

The time of one cycle, the period T, is one divided by the frequency: T = 1 / f. A 50 Hz current repeats every 1 / 50 = 0.02 s, or 20 ms, and a 12.5 Hz signal every 80 ms. The other way round, f = 1 / T, so a period of 500 µs is a frequency of 1 / 0.0005 = 2,000 Hz.