Tap any button in the Extensions row — 6, 7, maj7, 9, 11, or 13. Higher extensions include the lower ones, so tapping 9 on a minor triad gives you a minor 9th chord that already contains the 7.

How extensions stack

Once you've picked a root and a quality, extensions sit on top of the chord:

• 6 adds the major 6th — A on C. The 7th is not implied.
• 7 adds the minor 7th — B♭ on C. On a major triad this gives a dominant 7 like C7; on a minor triad it gives a minor 7 like Cm7.
• maj7 adds the major 7th — B on C — for chords like Cmaj7 or Cm(maj7).
• 9 adds the 9th and includes the 7th. Tap 9 on a Cm triad and you get Cm9, with degrees 1 ♭3 5 ♭7 9 and notes C E♭ G B♭ D.
• 11 adds the 11th and includes the 9 and the 7.
• 13 adds the 13th and includes the 9 and the 7. By default, Fretscape also stacks the 11, though real guitar voicings often leave the 11 out because it can clash with the 3rd — and a six-string can rarely fit every note anyway.

The chord name at the end of the Building row reads = Cm9, and the chord card on the right spells out all five degrees — the implied 7th included.

Add or omit modes

Long-press an Extensions button (or right-click on a computer) to open an add / omit menu. Add drops the implied lower extensions, so Bbadd9 is just a Bb triad plus a 9 — no implied 7. Omit keeps the larger extension label but leaves the selected implied note out of the voicing, producing names like Bb13(omit11). Add is offered on 9, 11, and 13 only; omit is offered whenever the note is actually in the chord. See How do I add or leave a note out of a chord? for the full walkthrough.

Major 7 vs dominant 7

The plain 7 button always gives you the minor 7th — the dominant sound on a major triad. To get the major 7th interval, tap maj7 instead. They're two different buttons because they're two different sounds: C7 (with B♭) is bluesy and unresolved, Cmaj7 (with B) is gentle and lit-up.

Removing or swapping an extension

Each extension you add shows as its own token in the Building row, with a small × for removal. To swap one for another — say, switching from Cm9 to Cm7 — tap the × on the 9 × token, then tap 7 to add it explicitly.

If you want to drop the chord further, remove the tokens one at a time. The chord name and voicings rebuild after each removal.