Key signatures consist of the sharps and flats at the beginning of a composition or section, which indicate the key of the composition or section.

A signature indicates either a major key or its relative minor key. There are 12 key signatures, one for each of the chromatic scale tones.

Table of Contents

  1. Spacing
  2. Key Changes



  • Flats:For the first flat, measure 3.5 spaces from the left side of the clef to the left side of the flat.


For each flat thereafter, measure 1 space from each flat to the next. 

KeySpaceFlatB KeySpaceFlatC KeySpaceFlatDKeySpaceFlatEKeySpaceFlatFKeySpaceFlatG


For the first sharp, measure 3.5 spaces from the left side of the clef to the left side of the sharp.




For each sharp thereafter, measure either 1 or 1.25 spaces from each sharp to the next, depending on the width of the horizontal lines of the sharps, which may vary.

KeySpaceSharpB KeySpaceSharpC KeySpaceSharpDKeySpaceSharpEKeySpaceSharpG KeySpaceSharpH



Note: See Meter for key signature spacing in relation to the time signature.


  • A double bar usually is placed before a key change.
  • It is traditional prtactice to cancel out the old signature before writing the new one (Ex. A), but that practice is now considered unnecessary by some publishers, and the double barline serves as an automatic cancellation of the old key signature, so the new one can be placed right after the double barline (Ex. B)
  • If a cancellation is used, it is best to arrange the music so that the cancellation can be written at the end of a system– the system is left open at the end– so that the next system begins with the new signature and not the cancellation.
  • A cancellation SHOULD be used if the change involves: changing from a major key to its parallel minor( Ex. C); changing from a minor key to its parallel major (Ex. D); changing from any key to C major or a minor. (Ex. E)