Chords in key finder
Choose a key and instantly see diatonic chords, 7th chords, common jazz extensions, roman numerals, common progressions, and related scale notes.
This tool includes basic triads, but it also shows the common 7th-chord and jazz-chord colors guitar players actually run into: maj7, m7, dominant 7, m7b5, dim7, maj9, m9, 9, 13, 7sus4, 7b9, and more.
Use the basic chords when you are writing simple progressions. Use the jazz options when you want smoother voice leading, richer harmony, or a more advanced sound.
Pick a key, then look at the roman numerals. Those numbers let you understand the function of each chord, not just memorize one key.
For example, a ii–V–I in C major is Dm7–G7–Cmaj7. In G major, the same idea becomes Am7–D7–Gmaj7.
| Degree | Triad | 7th Chord | Common Jazz Options |
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Chords in a key come from stacking notes inside the scale. In a major key, the basic triad pattern is major, minor, minor, major, major, minor, diminished. That gives you I, ii, iii, IV, V, vi, and vii diminished.
When you add one more third on top of each triad, you get the diatonic 7th chords. These are especially useful for jazz, blues, funk, soul, R&B, and more colorful rock harmony.
Jazz chords are often just regular chords with extra color tones added. A C chord can become Cmaj7, Cmaj9, C6, or C6/9. A G7 can become G9, G13, G7sus4, G7b9, or G7#9 depending on the sound you want.
You do not have to use all of these at once. Think of them as a menu of colors that can make a simple progression sound more professional.
Start with the notes of the scale, then build a chord from each scale degree by stacking thirds. In a major key, the basic pattern is I, ii, iii, IV, V, vi, and vii diminished.
In a major key, the common diatonic 7th chords are Imaj7, ii7, iii7, IVmaj7, V7, vi7, and vii half-diminished. Common extensions include maj9, m9, 9, 13, 7sus4, and 6/9 chords.
Yes. 7th chords are created by adding one more scale tone on top of each triad. They are still diatonic if all the notes come from the key.
A ii–V–I is one of the most common progressions in jazz and popular music. In C major, it is Dm7–G7–Cmaj7. In G major, it is Am7–D7–Gmaj7.
You do not need to master every jazz chord immediately, but learning maj7, m7, 7, and m7b5 will make chord charts, progressions, and lead playing much easier to understand.
Use this with the scale finder and progression analyzer to connect chords, keys, scales, and the fretboard.