Finding the key of a song you already like
A practical method for working out what key a record is in, by ear and by elimination.
Foundations — notes, intervals, keys · 8 min read
Start with the last chord, or the chord the song keeps returning to at the end of a phrase. Nine times out of ten in popular music that is the home chord, and the key is named after it. Songs that stubbornly refuse to end on home are usually doing it on purpose, and they are worth studying separately.
Then check the bass line. The lowest note under the chorus hook is nearly always either the home note or the fifth. If you hum the note the song feels like it wants to stop on, you are humming the tonic.
Finally, confirm by elimination: play the seven notes of your candidate key over the song. If one note sounds sour every time, your key is probably wrong by one accidental — try the key a fifth away, which differs by exactly one note.
- —The chord a song returns to is usually home.
- —Hum the note that feels like a full stop — that is the tonic.
- —Neighbouring keys differ by a single note; test rather than guess.
Pick three songs on your phone and find the key of each using the three checks above. Write your answers down before you verify them.
Open ChordCraft Lab1. How many semitones are in a major third?
2. What is the step pattern of a major scale?
3. Which white key sits immediately to the left of the group of two black keys?
4. Why can a song be transposed and still sound like the same song?