How to Figure Out the Chords of a Song by Ear
To figure out the chords of a song by ear, find the key first: the note the music comes home to. Then hum the lowest note at each chord change and find it on your instrument, because in most popular music the bass plays the chord’s root. Decide whether each chord is major or minor by its third. And check every guess against the seven chords the key contains — four of them, I, IV, V and vi, carry a large share of popular music on their own.
It works on any instrument, and the hardest steps are done with your voice.
Step 1: find the key by finding home
A key has a home note, the tonic, and a home chord. The last chord of the song or of the chorus is very often that home chord. Hum the note that feels like the end of the sentence, then play notes until one matches. That note names the key; whether it is major or minor is decided by the home chord, as in step 3.
Step 2: follow the bass, because it is usually the root
Do not try to hear every note of a chord at once; start with the lowest. In most popular music the bass plays the root of each chord, the note the chord is named after. Hum the bass line one change at a time and find each note. If the song is in C major and the bass goes C, G, A, F, you already have four roots.
If a bass note is too low to sing, hum it an octave higher: the name is the same.
How do you hear when the chord changes?
Listen to the bass again: when the harmony moves, the bass almost always moves with it, so a new bass note is the clearest sign of a new chord. Changes also tend to land on the first beat of a bar, so counting the beat tells you where to listen.
Step 3: major or minor is decided by one note
A major and a minor chord on the same root share two of their three notes. Only the third differs: four semitones above the root sounds bright, three sounds darker. Once you have a root, play both chords on it against the recording. One of them will clash.
The shortcut: a key only has seven chords
Build a chord on each note of a major scale, using only that scale’s notes, and seven chords come out, with qualities in an order that is the same in every major key: major, minor, minor, major, major, minor, diminished. That set is the harmonic field of the key. In C major:
| Degree | Chord |
|---|---|
| I | C |
| ii | Dm |
| iii | Em |
| IV | F |
| V | G |
| vi | Am |
| vii° | B diminished |
So once you know the key, the bass note predicts the quality. In C major, a bass on D is very probably D minor, and a bass on F is very probably F major. Listening for the third becomes a check, not a search.
A minor key uses the chords of its relative major: A minor has those of C major, with Am as home. The common exception is the fifth chord, often E major rather than E minor, because the major version leads home more strongly.
I, IV, V and vi cover a large share of popular music
Try the key’s I, IV, V and vi before anything exotic. A few patterns made of them come back constantly:
- I–V–vi–IV. The verse of “Let It Be” opens with it (C, G, Am, F), and “With or Without You” and “No Woman, No Cry” are built on it.
- I–vi–IV–V. The progression of “Stand by Me”.
- The twelve-bar blues. I, IV and V over twelve bars in a standard order, the form of “Johnny B. Goode”.
- ii–V–I. Subdominant, dominant, home: the basic move of jazz standards.
If your bass line matches the roots of one of these, you probably have the whole progression.
When the bass is not the root: inversions
Sometimes the bass gives you a chord that does not fit. The usual reason is an inversion: the same chord with its third or fifth in the bass instead of its root, written with a slash. G/B is a G major chord with B in the bass.
Inversions show up where the bass walks by step. A bass going C, B, A in C major is rarely C, B diminished, A minor. Much more often it is C, G/B, Am: the G chord turned so the bass can step smoothly down. In popular music, a bass on the seventh degree is far more often V with its third in the bass than the diminished chord.
The test: ignore the bass and listen to the chord above it. If the upper notes are a chord from the key and the bass is one of its notes, it is an inversion.
When a chord is not in the key
The most common outsider is a major chord where the key expects a minor one, usually on its way somewhere. In C major, D major in place of D minor tends to lead to G: it is the dominant of the dominant, a secondary dominant, written V/V. If an unexpected major chord resolves strongly to the next chord, read it as that chord’s dominant.
Work section by section, then practise the steps alone
Songs repeat. Work out one verse and one chorus, write them as roman numerals as well as chord names, and check the rest against them. Written as numerals, a progression is the same in every key, and you will recognise it on the next song.
Each step is easier to practise alone. The harmonic field lesson builds the seven chords of a key; the progressions lesson plays the patterns above and asks for the missing chord; the chord quality exercise drills major against minor until step 3 is quick; the inversions lesson trains you to ask what chord? and what is in the bass? separately. Then go back to the song.