A Quick Guide to Piano Chords

A thorough knowledge of chords can benefit every musician, and it doesn't take a college music degree to understand the fundamentals. This article will introduce the basics of chord theory and discuss tips and tricks to help you unlock the "secrets" of chordal harmony. We'll start with the old standby, a C major chord:

Using simple math we can use our knowledge of the C major chord to play any of the other 11 major chords. A C major chord is composed of 3 notes separated by two intervals. The first interval, a major third, begins at the C note, ends at the E note, and is composed of 4 half-steps: C to Db, Db to D, D to Eb and Eb to E. The second interval, a minor third, begins at the E note, ends at the G note, and is composed of 3 half-steps: E to F, F to Gb, and Gb to G.  (Note: Db could also be called C# depending on the key, but for the sake of simplicity only one note name has been provided.)

Armed with a knowledge of intervals, we can now use the C major chord as a template for any other major chord. For example, a D chord begins with the note D and contains a major third (from D to F#) that is composed of 4 half-steps: D to D#, D# to E, E to F and F to F#. The second interval, a minor third, begins at F#, ends at A, and is composed of 3 half-steps: F# to G, G to G#, and G# to A:

Now, returning to the original C chord example:

This chord  can be changed from a major chord to a minor chord by moving the middle tone (an E in this case) a half-step down. This effectively inverts the intervals, putting the minor third (3 half-steps) in the lower half of the chord and the major third (4 half-steps) in the upper half. What a difference a half step makes!

Again, this same process could be applied to any of the twelve keys to determine any minor chord. For example, a D minor chord contains the same intervals as a C minor chord but begins on the D note and ends on the A note. It contains a minor third (3 half-steps) in the lower half of the chord and a major third (4 half-steps) in the upper half:

Returning to the C minor chord example:

To turn this chord into a diminished chord, all we need to do is lower the fifth tone as follows:

Now we have  two minor thirds (three half steps) stacked on top of each other. Again, this process can be used to determine the notes that make up any diminished chord. For example, a B diminished chord begins with B and is composed of two minor thirds (three half-steps): from B to D and D to F.

Now we will discuss 7th chords, which can be made by adding a fourth note to any of the chords discussed above and which add variety and interest to music. (There are also 9th, 11th and 13th chords, as well as suspended chords, 6/9 chords, augmented chords and many others, but for the sake of brevity these additional chords will be discussed another time.)

There are several types of 7th chords. First we will discuss the dominant 7th. It is formed by adding an interval of a minor third (3 half-steps) to a major chord, as follows:

A major 7th chord can add a contemporary/jazz sound to songs and is formed by adding an interval of a major third (4 half-steps) to a major chord:

 A minor 7th chord is formed by adding a minor third (3 half-steps) to a minor chord:

And finally a diminished 7th chord is formed by adding a minor third (3 half-steps) to a diminished chord:

Don't be confused by the esoteric music rule requiring the use of a double-flat to notate diminished seventh chords; a "B double-flat" is really just an A.

Before ending this article I'd also like to point out that the notes all of the chords discussed so far can be played in ANY ORDER to enhance variety and interest as well as improving playability, preventing muddied sounds in the lower register of the piano and preventing collisions between the right and left hands. These variations are called "chord voicings" and sometimes are notated with a slash, as in G/D. This doesn't mean you can play a G chord OR a D chord, it means you should play a G chord with a D note at the bottom, like this:

Sometimes, in addition to inverting chords, you can drop less important notes. A standard G7 chord in the root positions looks like this:

But it is often inverted and "voiced" with only three notes (the 5th tone is dropped because it's function is less important that of the other three notes):

When it comes to chord construction, a little knowledge really can go a long way! Once these fundamentals have been internalized, you'll be able to spend less time looking through chord reference books and more time playing the songs you love.