Intervals and the differences between your 7th chords

14 May

Hi there,

Thanks for taking an interest in my blogs so far.

Most guitarists will look at sheet music or tab at some point during their playing lives and will come across chords like Cmaj7, C7 and Cminor7 but not actually understand why they are called these and why they work with other chords

I’ll just cover 3 types of 7 chords in this blog as they tend to be the most popular and the ones that you’ll see

As you know your chords are built up of various intervals, the intervals used to make these 3 7th chords are:

(b3) Minor 3rd – Is 1 1/2 tones in size

(3) Major 3rd – is 2 tones in size

(5) Perfect 5th – is 3 1/2 tones in size

(b7) Minor 7th – is 5 tones in size

(7) Major 7th – is 5 1/2 tones in size

A Tone is 2 notes i.e. G to A or E to F#

A Semitone is 1 note i.e. G to G# or B to C

The numbers on the left in brackets are what these intervals are often abbreviated to for ease of writing and saying them out loud. Just like when you say Lol in a text message instead of laughing out loud!

Your Major 7 chords comprise of a root (1), 3, 5 and 7

Your Minor 7 chords are made up from 1, b3, 5 and b7 intervals

Your Dominant 7 (7) chords are made up from 1, 3, 5 and b7 intervals

The reason these chords sound like they do and differ from the others is due to the intervals within them. It’s also why you have to be careful in your songs which ones to use as the wrong type of 7th chord could clash with notes in that key.

Let’s take a few examples of 7th chords:

Cmaj7 would contain the notes C, E, G and B

C –> E       C –>G                 C –>B

2tones (3)   3 1/2tones (5)     5 1/2 tones (7)

B7 would contain the notes B, D#, F# and A

B –> D#      B –> F#             B –>A

2tones (3)   3 1/2tones (5)    5 tones (b7)

So as you can see there are slight differences in the make up of all these 3 types of chords, and the differences in the intervals produces their signature sound

Learning these will really help you to carefully pick which chords to use in a song and you’ll be able to look at a piece of music with a particular 7th chord in it, and if it doesn’t sound right, then you can check the correct notes with the above formulas.

Also knowledge of these are essential for learning arpeggios as you’ll be using all these various intervals in different positions to improvise over these chords to highlight their features.

Plus if you’re in a band, or want to play other instruments like the piano, a Gmaj7 chord is going to be the same on any instrument so you’ll give yourself a big advantage.

Many thanks for reading



You can also find other useful tips @jsmusicschool


Posted by on May 14, 2012 in Music Theory


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2 responses to “Intervals and the differences between your 7th chords

  1. Richard McCargar

    May 14, 2012 at 8:56 pm

    I’ve been playing by ear for years, and it’s about time I learn the more than the basics I now understand. I’m posting guitar licks/solos with tab on my blog, and this info could only help. Thanks for posting.

    • jsmusicschool

      May 14, 2012 at 9:53 pm

      No problem, glad you find my blog useful


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