A gigahertz is a unit that measures how fast something happens, specifically one billion cycles or vibrations per second.

You'll most often see gigahertz (abbreviated GHz) describing computer processor speeds. When a computer chip runs at 3 gigahertz, it means tiny electronic switches inside flip on and off three billion times every second. That incredible speed is what lets your computer load websites, run games, and process information quickly.

Radio waves and Wi-Fi signals are also measured in gigahertz. Your home Wi-Fi router might broadcast at 2.4 GHz or 5 GHz, which describes how rapidly the radio waves oscillate as they carry data through the air.

Higher gigahertz numbers usually mean faster performance, though that's not the whole story. A 4 GHz processor isn't automatically twice as fast as a 2 GHz one because other factors matter too, like how efficiently the chip is designed. Still, gigahertz gives you a useful way to compare similar devices and understand just how astonishingly fast modern technology operates.