If you've ever listened to the radio, used a microwave, or even just seen a color, you've interacted with frequency. But what is frequency? In the simplest terms, frequency is a measure of how often a repeating event occurs in a given amount of time.

Think of waves in a pond. If you tap the water slowly, the waves are far apart. If you tap it quickly, the waves are close together. Frequency is the measure of how many of those wave crests pass a single point every second.

The Official Unit of Frequency: Hertz (Hz)

The standard unit of frequency is the Hertz, named after the German physicist Heinrich Hertz. The Hertz definition is beautifully simple:

1 Hertz (Hz) = 1 Cycle per Second

If a wave completes one full cycle in one second, its frequency is 1 Hz. If it completes ten cycles in one second, its frequency is 10 Hz.

Understanding the Metric Prefixes: kHz, MHz, GHz

Because frequencies can be incredibly high, we use standard metric prefixes to make the numbers manageable:

• Kilohertz (kHz): 1,000 Hz (Thousand cycles per second)

• Megahertz (MHz): 1,000,000 Hz (Million cycles per second)

• Gigahertz (GHz): 1,000,000,000 Hz (Billion cycles per second)

Converting between these is essential. For instant calculations, use our free Frequency Converter.

Real-World Examples of Frequency

• Sound: The pitch of a sound is determined by its frequency. A low bass note might be around 50 Hz, while a high-pitched whistle could be 15,000 Hz (or 15 kHz).

• Radio: Your favorite FM radio station broadcasts at a specific frequency, like "101.1 MHz." This means the radio wave is oscillating 101.1 million times every second.

• Computers: The speed of a computer's processor (CPU) is measured in Gigahertz (GHz). A 3.2 GHz processor performs 3.2 billion cycles every second.

• Light: The color of light is determined by its frequency. Red light has a lower frequency than blue light.

To see how to convert between these units, check out our guide: Hz to MHz to GHz: A Simple Conversion Chart.