A count off, count in, or lead-in is a verbal, instrumental or visual cue used in musical performances and recordings to ensure a uniform entrance to the performance by the musicians and to establish the piece's initial tempo, time signature and style. Although a count off usually lasts just one or two bars, it is able to convey the music's style, tempo, and dynamics from the leader (such as the conductor, bandleader or principal) to the other performers. A count off is generally in the same style of the piece of music—for instance, a joyful swing tune should have an energized count off. A misleading lead-in, one which indicates a different meter than that of the piece, is a false trail. Counting off is evident in musical genres other than Western classical and popular music; Ghanaian ethnomusicologist J. H. Kwabena Nketia has observed the benefits of such techniques in West African music.
A silent count off, such as those given by an orchestral conductor using a baton, may be given as a value "in front" (e.g. "eight in front" refers to a count off of eight beats).
In recorded music, the final two beats of the count off (one, two, one—two—three—four) are often silent to avoid spill onto the recording, especially if the piece has a pickup. The count off is typically edited out after the recording has finished. There are, however, instances where the count off is deliberately kept on a recording—sometimes even edited onto a recording. In the case of "I Saw Her Standing There" by The Beatles, the count off was edited onto a different take of the song. A recorded count off can be made by musicians through an open microphone or through the studio's talkback system, the latter being done by non-performing personnel such as the producer or engineer. The inclusion of a count off in a studio recording may give the impression of a live performance, as on the Beatles' "Sergeant Pepper's Lonely Hearts Club Band Reprise" (1967).