Leger line

A leger line (sometimes spelt ledger line) is a tool of musical notation to express notes that do not fall within the range of the musical staff. A short line (slightly longer than the note) is drawn parallel to the lines on the staff, corresponding to where the staff line would be if the note were in range (see Figure 1). For notes close to the staff, leger lines are much less confusing than a clef change, and more natural to notate. A good rule of thumb is to use no more than three or four leger lines outside of the staff; more than that are very hard to read. The solution to excessive leger lines is to use 8va notation, or to change the clef for long passages.

Figure 1. leger lines above the staff, using eighth notes. The lines on the right are too far off the staff and should be written in a different clef or with an 8va notation.