How to Add 7ths to the Major Scale Chords on the Guitar
You begin playing new chords on the guitar by adding 7ths to major scale chords. Adding 7ths is a good place to start because it’s in keeping with the consecutive 3rds formula that triads follow (1-3-5-7 are all consecutive 3rds).
Plus, you can easily add 7ths without needing to suspend a 3rd or interfere with the rest of the triad. Using the G major scale and its basic triads as a starting place, you add a 7th to each chord by counting up seven from each scale degree.
Here are seven diagrams, all with the same notes from the G major scale. Each diagram counts from a different starting point so you can see the 7th of each scale degree. Starting points and 7ths are shown in black. The starting points are the roots to each triad/chord in the scale. You add the 7ths to the basic triads to create 7th chords.
A 7th is a 3rd above a 5th and keeps with the 3rds sequence used to build the basic triads. In the major scale, counting 1-2-3 is a 3rd, but so are 3-4-5 and 5-6-7. In all, you build a 7th chord by using the intervals 1-3-5-7, which are all a 3rd apart.
There are two types of 7th intervals. One type — the major 7th — is almost an octave, missing it by just a half step and named after the type of 7th that occurs in the major scale. You see major 7ths on G and C in here.
The other type — a minor or f7th — misses the octave by a whole step and is named by the type of 7th that occurs in a minor scale. You see minor 7ths on A, B, D, and E.
Here is what the basic major and minor triads in G look like after you add 7ths to create 7th chords. The notations in parentheses illustrate the most common ways to write the chord names.
G: 1-3-5-7, G-B-D-Fs, G major 7 (Gmaj7, GM7, G)
A: 1-f3-5-f7, A-C-E-G, A minor 7 (Amin7, Am7, A-7)
B: 1-f3-5-f7, B-D-Fs-A, B minor 7 (Bmin7, Bm7, B-7)
C: 1-3-5-7, C-E-G-B, C major 7 (Cmaj7, CM7, C)
D: 1-3-5-f7, D-Fs-A-C, D dominant 7 (D7)
E: 1-f3-5-f7, E-B-G-D, E minor 7 (Emin7, Em7, E-7)
Fs: 1-f3-f5-f7, Fs-A-C-E, Fs minor 7f5, half diminished 7th (Fsmin7f5, Fsm7f5, Fs-7f5, Fs’)
When you add the 7ths in the preceding list to standard major and minor barre chords, you get the new chord shapes shown in here.
You can see this at 7th Chords in G.
In this example the numbers represent intervals, which are important to look at so that you see how each chord shape is constructed. You’re on your own to work out fingerings, but your fingers will easily fall into place with these chord shapes. Try playing forward and backward through the scale with 7th chords.
You can also play through 7th chords in the open position, as shown here. Again, the numbers represent intervals. Work out your own fingerings.
The 7th chord sequence in the G major scale is the same in all major scales. All major scales naturally produce maj7 chords on their 1st degrees, m7 chords on their 2nd degrees, and so on.
Here are tabs with 7th chords in the keys of A, C, and D. With each key, you get to know some new 7th chord shapes. In most cases, you can figure out where the 7th is in each shape by playing the regular major or minor form first, then switching to the 7th chord.
The new note that’s added to make the chord shape a 7th is the 7th! You can move these shapes away from the open position and use them as full or partial barre chords to play 7th chords for other notes around the fretboard.