Microwaves are a form of electromagnetic radiation, just like visible light, but with much longer wavelengths. The wavelength of microwave radiation typically ranges from about 1 millimeter to 30 centimeters. This means that microwaves have frequencies between 300 megahertz (MHz) and 300 gigahertz (GHz).

The wavelength of a microwave oven is typically around 12.24 centimeters (4.8 inches), which corresponds to a frequency of 2.45 gigahertz (GHz). This is the wavelength that is most commonly used for microwave ovens because it is able to penetrate food without being absorbed by water molecules. This allows food to be heated quickly and evenly.

Other appliances that use microwaves include radar systems, satellite communications, and medical imaging devices.