About

Information about The Harmony Encyclopedia.

What this is

The Harmony Encyclopedia is a free reference for the harmony of Western common-practice music: the intervals, chords, scales, cadences and voice-leading conventions that underpin most tonal music written since roughly 1600, and a good deal of popular music written since. In addition, comprehensive examples are gathered, and every example is rendered as real notation, on a real, interactive staff.

It exists because most of this material is either locked inside expensive textbooks or scattered across the internet. The goal of The Harmony Encyclopedia is to make music harmony accessible for all.

Note that this project is still very early in development and a work in progress. If you find any errors, be sure to report it in the contact page.

Where the data comes from

None of it is scraped from other sites or licensed from a dataset. Every table here is produced by a generator script that encodes the conventions of common-practice theory as they are ordinarily taught, and then applies them exhaustively toevery chord type built on every root, every mode of every scale, all 24 keys.

It is worth being clear that some of the material and categorizations listed in this site are not universally agreed upon. The site is built on a set of rules that are widely taught and chosen to be representative of the common-practice tradition, but there are often other traditions and other ways of categorizing the same material.

What this site collects

Page views are counted through Vercel Web Analytics, which records the page visited, the referring site, and coarse details such as country and browser. It is cookieless (for now).

Built on

Using the content

The reference content on this site, meaning the tables, the descriptions, the notated examples and the underlying data, is published under the Creative Commons Attribution-ShareAlike 4.0 International licence.

You are free to:

  • Copy and redistribute it in any medium or format.
  • Adapt it, remix it, transform it and build on it, for any purpose, including commercially.

On two conditions:

  • Attribution. Credit The Harmony Encyclopedia, link back to it, and indicate whether you changed anything. Something like “The Harmony Encyclopedia (theharmonyencyclopedia.com), CC BY-SA 4.0” is plenty.
  • ShareAlike. If you build on it and distribute the result, the result carries the same licence. What is freely available here stays freely available downstream.

Warranty

This material is offered as is, without warranty of any kind. It is compiled carefully but might still contain mistakes.

If you are relying on it for an exam, a submission, a publication, check it against your own authority first.

Corrections

If you find an error, or have comments or suggestions on how to improve the site, please report it, or write to aaronx@berkeley.edu.

Last updated 27 August 2026