Chord Extensions

     In this post I will be showing you how to make chords with extensions and how to read them. You will also find a table with examples of common chord extensions, that you are likely to come across, together with the interval relationships for building that specific chord over that root.

All the notes that are not the root, 3^rd, 5^th and 7^th degrees of a given chord are called extensions. That said, there are only three extensions left to stack before we return to the root – the 2^nd or 9^th; the 4^th or 11^th; and 6^th or 13^th.

     Notice that I included the simple and compound interval relationship between the root and the remaining extensions. Each type of chord extension will have a distinct feel and it can be used to add richness and depth to your music. Also, extensions introduce a certain tension in the harmonic progression which can also be used to lead or resolve to the next chord:

     One thing to be aware of is that chord extensions change their relative intervallic quality according to the position of the chord root in the scale or mode it refers to, and thus are spelled differently – they can be sharpened (#11 or #9), flattened (b9, b13) or natural (11, 13, 9), even though we are on the same scale. For instance, if we consider the C major scale that has no sharps or flats, the 11^th of Dm is natural because it’s based on a perfect fourth between D and G, and thus is spelled like Dm¹¹; while the 11^th of F major is spelled F maj^#11 because it’s based on an augmented fourth between F and B:

     Here is a table with the most common chord extensions and their spellings. It is not by any means a comprehensive list of all the possible extensions combination but hopefully it will shed some light on how chords may be spelled according to its extensions:

     Keep in mind that when you see a chord spelled like C¹³, it means that the previous extensions are implied in the chord formation – the 9^th and 11^th. Also, in this case, this implies a dominant chord with minor 7^th and if you want to indicate that the chord has a major seventh then you will need to write Cmaj¹³. Also, the prefix “add” means that the following extension is added to the chord without implying the previous ones. For instance, a Cm add¹¹ only adds the 11^th to the Cm chord without implying the 7^th or the 9^th.