Scale Degrees & Chord Function
Why do certain chords sound good together? Because they come from the same key, each with its own “scale degree” and function.
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Seven degrees in a key
In a major key, start on the tonic and stack a triad on every other scale note, and you get seven chords, numbered 1–7 in order (usually written as the Roman numerals I–VII).
Take C major: 1=C, 2m=Dm, 3m=Em, 4=F, 5=G, 6m=Am, 7°=B diminished. Which degrees are major and which are minor is the same in any major key (major, minor, minor, major, major, minor, diminished).
Three functions: tonic / dominant / subdominant
Think of the three functions as a trip out the door: the tonic chords (degrees 1 and 6) are “home” — stable, you've arrived; the dominant chords (degrees 5 and 7) are “out there” — farthest from home, the most tension, the most pull to come back; the subdominant chords (degrees 4 and 2) are the “bridge” — the transition from home out into the world.
A chord progression is really just leaving and coming back over and over: “out the door → over the bridge → out to the tensest point → home.” The three most common routes home: home → bridge → out there → home (the most complete); home → bridge → straight back home (gentle); home → straight out there → home.
- 💡 Once you know the degrees, you can instantly work out which chords to use even when a song moves to a different key — that's the underlying logic of reading number charts like “1645.”
Why the “magic progressions” sound good
1–5–6–4 (in C that's C–G–Am–F) = tonic → dominant → tonic (minor) → subdominant, with tension and release trading off the whole time, so it sounds both smooth and catchy — countless pop songs are built on it.
One bar of count-in first, then the chord changes automatically each bar. Get it smooth slowly, then speed up bit by bit.
Loop along with C–G–Am–F (1–5–6–4): as you listen, map each chord to the leaving-and-coming-home tension of “tonic → dominant → tonic (minor) → subdominant,” and feel why it sounds so smooth and catchy at the same time.
Chords in this lesson
Tap the 🔊 under each diagram to match every chord's sound to its shape.
⏱️ Cycle this lesson's chords to a beatPractice switching without stopping (one-minute changes) — first learn each chord by ear and shape, then drill clean changes between them.Expand Collapse
Switch back and forth between this lesson's chords to the beat below.
One bar of count-in first, then the chord changes automatically each bar. Get it smooth slowly, then speed up bit by bit.
Want to count how many changes you can do in 60 seconds? Head to the one-minute changes drill.
Go play these
Songs that fit this lesson's technique and chords — pick one and practice in the library:
- Em–Am Two-Chord Jam · Original exerciseEm · Am
- Mary Had a Little Lamb · American traditional nursery rhyme (public domain)C · G
- Kumbaya · American traditional spiritual (public domain)C · F · G
- The Four-Chord Jam: G–D–Em–C · Original exerciseG · D · Em · C
- Ode to Joy · Beethoven (public domain)G · D
- Twinkle Twinkle Little Star · French traditional melody (public domain)G · C · D
Practice checklist
- In the key of C, name each of the chords for degrees 1–7 in order.
- Play through C–G–Am–F, feeling the “leaving and coming home” motion as you go.