A chord chart answers one question: how do I play this chord. Chord Options is for the questions on either side of it. Which chords are available to me here, and why does each one work?
Pick a key and you get every chord it offers: the seven it is built from, the secondary dominants that point at them, the tritone substitutions that replace those, and the chords borrowed from the parallel key. Each one says what it is doing there, which chord it usually goes to next, and why.
Chord Options is free, carries no advertising and asks nobody to sign up. It is one person’s project with nothing behind it, so people find it only when somebody points them at it.
If it has been useful to you, a share, a link, a post or a mention helps it reach those who need it.
The chord shapes originate in chords-db, an open dataset of guitar chord fingerings. Which of them count as Common, along with a few hundred additional chord shapes, comes from how often each shape is played across about 3,300 transcribed songs: the chord diagram data released with D’Hooge, Bigo, Déguernel and Martin, Guitar Chord Diagram Suggestion for Western Popular Music (Sound and Music Computing, 2024), drawn from DadaGP and mySongBook and used under the Open Database License. The common shapes are what a chord page opens with.
Everything beyond them is derived rather than collected. Shells, drop 2, drop 3, rootless and triad voicings are generated from the intervals of each chord and the geometry of standard tuning. The generator places each voicing on every string set it can be played on, rejects anything outside a five-fret stretch, and keeps a bounded number per string set and inversion, so the result is the grid a method book teaches rather than every shape that is mathematically possible.
A generator that produces plausible-looking nonsense is worse than no generator, so every build runs the output back through the theory it came from.
That last figure is the credibility test. Run against the shapes in chords-db that are comparable, meaning three and four notes, the generator independently arrives at two-thirds of them. The rest are mostly five and six-string CAGED shapes it is deliberately not trying to make.
The explanations in the app are not folk knowledge. What a degree of the key is for, what a suffix does to that job, and where a chord tends to go next are three different claims of three different kinds, and none of them is written straight into a template: each sentence the app generates is produced by a rule, and the rule states what is being claimed. A claim with no rule behind it is one the app has started making on its own authority, and it does not ship.
Naming a shape works the other way round. The notes are read off the fretboard in standard tuning and every chord symbol they can spell is listed, ordered by the bass note. The candidate symbols come from tonal; which of them is right in context is a question the shape alone cannot settle, so the chord identifier gives every reading and says what each one is claiming.
Every chord’s data is a static JSON file, and it is public.
/data/chords/<key>/<suffix>.json
/data/chords/C/maj7.json Cmaj7
/data/chords/Csharp/m7.json C#m7 (a sharp is written "sharp")
/data/chords/C/slashE.json C/E (a slash is written "slash")Each file holds the derived voicings for that chord, the tensions available over its shell, and the notes and fret string of its picture. 550 chords across 12 keys. See one, or start from the index of every chord.
Licence. The data is published under CC BY 4.0. Use it for anything, including commercially; the one condition is attribution, which a link back to chordoptions.com satisfies. The common chord shapes come from chords-db and carry its terms; what is licensed here is this site’s derived voicings, tensions and chord-tone data, and the files they are published in.
Every figure on this page comes out of the build, and the data it describes is public.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.