ABC notation is a plain-text system for notating music using ASCII characters. Designed so melodies can be written, read and transmitted as simple text files, ABC is human-readable and machine-processable. It is commonly used for single-line melodies such as folk tunes, dance music and hymns, but supports many features needed for multi-voice and ornamented music.

Core features and syntax

An ABC file typically begins with a small header that identifies the tune and its parameters using short field markers, for example X: (reference number), T: (title), M: (meter), L: (default note length) and K: (key). Notes are written with letters A–G; accidentals use symbols such as ^ for sharp and _ for flat; octave shifts use comma and apostrophe. Note length, bar lines, tuplets, chords (in brackets), grace notes and simple decorations are all representable.

Example (very short): X:1 T:Sample M:4/4 L:1/8 K:G GABc d2|e4 z4. Files commonly carry the .abc extension and can be converted into standard notation or audio by a variety of programs.

History and development

The format was created and popularized by Chris Walshaw as a compact way to share traditional tunes using only plain ASCII text. Over time a community of users and developers extended the language with conventions for multi-voice arrangements, chord symbols, lyrics and advanced formatting. Because it is text-based it easily integrates with search, version control and web publishing workflows.

Uses, tools and community

  • Archiving and sharing tune collections in plain text.
  • Rendering to standard notation, MIDI or audio via converters and libraries.
  • Embedding in web pages and interactive players through software that reads ABC.

Many free and open-source tools read and write ABC and convert between ABC and other formats. For documentation, libraries and converters see the format resources and implementations linked by the community: official documentation and tools.

Because ABC is both concise and readable, it remains popular among folk musicians, archivists and educators. It trades some of the editorial control of full engraving systems for simplicity and portability, but when combined with modern converters it can produce high-quality scores suitable for print and performance.