The abc standard

This is the home page for the abc standard, the (semi-formal) description of the rules of abc. It contains links to different versions of the standard and to development work.

If you wish to link to the standard, it is recommended that you link to this page,, rather than to a specific version.

Draft version

The new draft version of the standard is at

Current version

The current version of the standard is at:

Development work

See the following pages:

Older versions

A number of older versions are available:

Formal specifications

Henrik Norbeck has provided formal specifications of the standard in Backus-Naur Format available at:

Other developments

Other developmental work on abc notation can also be found at:


Changes to the standard tend to be discussed at the abcusers mail list or occasionally in the discussion forum: