If you play jazz, rock, folk, or really any style of music other than classical, chances are you regularly encounter chord symbols like C or Em or G7 or Fmaj7 or D13#11 or A9sus. If you know your major and minor triads but are less comfortable with anything beyond that, this is for you.

Actually, I would suggest the real starting point for learning your chords is the major scale. If you know your major scales, you can construct all chords using just a handful of rules. OK, it's actually a pretty big handful, but it's not that bad, I promise. And we'll focus on just triads (four types) and seventh chords (six types) for now.

Ready to get started? Think about a major scale, and number the notes within that scale 1-2-3-4-5-6-7. Here are the rules for building chords from there:

  1. A root by itself indicates a major triad, which is scale degrees 1, 3, and 5.
  2. A "7" after the root normally means scale degree b7. So, unless you hear otherwise, flat the seventh. Why? Because the chord 1-3-5-b7 is the most important type of seventh chord (it's called a dominant seventh) and people just wanted to be able to write it as C7. But what if someone wants you to play scale degree 7 instead of b7? Read on...
  3. "major" in a chord symbol means use 7 instead of b7. Don't flat the seventh - that's what "maj" in a chord symbol always means, regardless of what else is going on. So Cmaj7 is 1-3-5-7. BTW, instead of "maj", another common abbreviation is "ma", but you will also see "M", "Ma", "Maj", or a triangle.
  4. "minor" in a chord symbol means use b3 instead of 3. Flat the third - that is what "m" in a chord symbol always means, regardless of what you see around it. So, Cm is 1-b3-5 (because C by itself is 1-3-5), and Cm7 is 1-b3-5-b7 (because, C7 is 1-3-5-b7). How about Cm(maj7)? The "m" says flat the third, the "maj" says don't flat the seventh - so, 1-b3-5-7. BTW, instead of "m", many musicians use "mi", and you will also sometimes see "min" or "-".
  5. "diminished" in a chord symbol means b3 and b5. Furthermore, if there is a seventh (which would normally already be flatted), flat it again - bb7. Seriously, double flat. So, Cdim is 1-b3-b5, and Cdim7 (also called fully diminished) is 1-b3-b5-bb7. You'll also see "o" or a circle or degree sign to indicate diminished.
  6. "half-diminished" is like diminished, but withb7 instead of bb7. The symbol is a circle with a slash through it (which many browsers can't display, so I'll use 0). So, C07 is 1-b3-b5-b7. This happens to be similar to Cm7 except with a b5, so Cm7b5 is another name for this. In some ways, that's a better name, because it actually has more ion common with minor seventh chords than with fully diminished seventh chords, but it's mostly in the jazz world you see that.
  7. "augmented" means #5. So, Caug is 1-3-#5. Often indicated with a "+".

Those are the rules for most of the basic symbols and abbreviations you see in chords. You may not realize it, but we managed to cover all four types of triads (major, minor, diminished, augmented) and all six types of seventh chord (dominant seventh, minor seventh, major seventh, minor-major seventh, diminished sveenth, half-diminished seventh) with these seven rules.

Now, it might not seem like such a win that we managed to learn ten chords using "only" seven rules. But the cool thing is, those same seven rules serve us as we eventually look at more complex chords, with sixths, ninths, flat thirteeths, suspensions, and more. So for instance, the fact that "minor" always means "flat the third" tells us that the only difference between C6 and Cm6 is, you guessed it, the third. Both have the same sixth - the 6 from the major scale. And Cmaj7 and Cmaj9 both have scale degree 7, while C7 and C13 both have scale degree b7. Plenty more goodies like that to learn, but I'll stop here for now. For more, check out my free handouts on musescore.com, or better yet, my online course Basic Music Theory.

By the way, one reason I have chord symbols on the mind right now is that we have just released MuseScore 3.5, and one of its major new features is that it can actually play back your chord symbols! It understands all of these same rules, and it doesn't care if you use "m", "mi", "min", or "-" -to indicate minor - MuseScore knows they all mean, flat the third.

To download the latest version of MuseScore (free and open source music notation software, in case you aren't already familiar with it), see https://musescore.org/download.

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