"Guitar tuner" redirects here, but can also refer to the string tension adjusters also called machine heads. For the radio receiver component, see Tuner (radio)

In music, an electronic tuner is a device that detects and displays the pitch of musical notes. Simple tuners indicate—typically with a needle-dial, LED, or LCD display—whether a pitch is lower, higher, or equal to the desired pitch. Software applications can turn a smartphone, tablet, or personal computer into a tuner. More complex and expensive tuners indicate pitch more precisely.