About CHORDZOID

CHORDZOID is a guitar chord reference you can play. Every chord has its own page with the shapes, the notes, the formula, the chord on a stave, and a way to hear any of it.

108 chords, each on its own page

Twelve roots and nine qualities, from plain major to suspended, diminished and augmented. Each page shows the shapes we consider worth learning first, and tapping a string plucks it so you can check yourself by ear rather than only by eye.

Why the note names are worked out rather than looked up

Most chord sites keep a table of twelve note names and index into it. That table is wrong for every altered chord, because the same pitch has different names depending on the chord it sits in. CHORDZOID used to print E major, the first chord anyone learns, as E, Ab, B. It is E, G sharp, B, and 41 of the 108 chords were wrong the same way.

The fix was to stop looking names up. The letter now comes from the chord degree and the accidental from the pitch, so a third is always spelled on the third letter up. On a guitar there is a second step: a shape sounds only some of the chord's notes and repeats others across six strings, so each sounded fret is traced back to the degree it is playing before it can be named. The fret diagram is handed its names, because a fretboard has no way of knowing which chord it is drawing.

Checked against something we did not write

A test suite that agrees with itself cannot catch an idea that is consistently wrong, so every one of the 108 chords is also compared against tonal, an independent music theory library, on every build. The formula printed beside the notes is derived from the same data rather than typed, so it can never disagree with them.

Learn

Alongside the reference there is a short course that starts from nothing: a handful of chords, then the changes and songs they unlock. Your progress is kept in your own browser.

Who makes it

CHORDZOID is one of a small family of music tools by an independent developer, alongside a guitar tuner, a metronome and a piano chord reference. Corrections are welcome at [email protected].