A song key is the note a piece of music treats as home, called the tonic, plus the scale built on it. A song in C major centres on C and mostly uses C, D, E, F, G, A and B. The key decides which notes and chords sound settled. Every key’s notes are in the music key chart.
What does the key of a song mean?
Play the last chord of almost any pop song and it feels finished. That resting point is the tonic, and the key is named after it: a song that comes home to G, using the G major scale, is “in G major”. The melody and chords move away from the tonic to build tension and return to it to resolve.
The key is a set of notes, not a single sound. That is the difference from pitch, which is how high one note sounds (what pitch is in music). Moving every note of a song up or down by the same amount changes its key; key change vs pitch change explains how the two relate.
The parts of a key: tonic, scale and chords
Each key has seven scale notes, numbered 1 to 7 (scale degrees). Building a chord on each note gives the key’s family of chords, written in Roman numerals. Here are C major and its relative minor, A minor, which share the same seven notes:
| Degree | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| C major notes | C | D | E | F | G | A | B |
| C major chords | C (I) | Dm (ii) | Em (iii) | F (IV) | G (V) | Am (vi) | Bdim (vii°) |
| A minor notes | A | B | C | D | E | F | G |
| A minor chords | Am (i) | Bdim (ii°) | C (III) | Dm (iv) | Em (v) | F (VI) | G (VII) |
The 1, 4 and 5 chords (C, F and G in C major) carry most songs. That is why the chords of a song are a strong clue to its key.
Major and minor keys
A major and a minor key differ in the pattern of steps between the scale notes. A whole step is two semitones (W), a half step is one (H):
- Major scale: W–W–H–W–W–W–H. The third note is 4 semitones above the tonic (a major third), which gives the bright, stable sound.
- Natural minor scale: W–H–W–W–H–W–W. The third is only 3 semitones above the tonic (a minor third), which sounds darker. Harmonic and melodic minor raise the 7th (and 6th) note in some passages.
Mood labels such as “happy major, sad minor” are a rough guide only; tempo, rhythm and lyrics matter as much. To hear the same song in the other mode, use the major to minor converter.
Key signatures: the sharps and flats of each key
Sheet music shows the key with a key signature: the sharps or flats written at the start of each line. Sharps are always added in the order F♯ C♯ G♯ D♯ A♯ E♯ B♯, and flats in the reverse order B♭ E♭ A♭ D♭ G♭ C♭ F♭. Each major key shares its signature with one minor key, its relative minor.
| Major key | Key signature | Relative minor | Tonic in octave 4 (A4 = 440 Hz) |
|---|---|---|---|
| C major | none | A minor | 261.63 Hz |
| G major | 1♯ (F♯) | E minor | 392.00 Hz |
| D major | 2♯ (F♯ C♯) | B minor | 293.66 Hz |
| A major | 3♯ (F♯ C♯ G♯) | F♯ minor | 440.00 Hz |
| E major | 4♯ (F♯ C♯ G♯ D♯) | C♯ minor | 329.63 Hz |
| B major | 5♯ (F♯ C♯ G♯ D♯ A♯) | G♯ minor | 493.88 Hz |
| F♯ / G♭ major | 6♯ (F♯ C♯ G♯ D♯ A♯ E♯) or 6♭ | D♯ / E♭ minor | 369.99 Hz |
| D♭ major | 5♭ (B♭ E♭ A♭ D♭ G♭) | B♭ minor | 277.18 Hz |
| A♭ major | 4♭ (B♭ E♭ A♭ D♭) | F minor | 415.30 Hz |
| E♭ major | 3♭ (B♭ E♭ A♭) | C minor | 311.13 Hz |
| B♭ major | 2♭ (B♭ E♭) | G minor | 466.16 Hz |
| F major | 1♭ (B♭) | D minor | 349.23 Hz |
Each step down the table adds one sharp or, from D♭, removes one flat: that order is the circle of fifths. The Hz column uses standard tuning and 12-tone equal temperament.
Relative and parallel keys
- Relative keys share all seven notes and the key signature but have a different tonic. The relative minor starts on the 6th note of the major scale, 3 semitones below the major tonic: C major ↔ A minor, G major ↔ E minor.
- Parallel keys share the tonic but not the notes: C major and C minor. C minor has three flats (B♭, E♭, A♭).
Because relative keys use the same notes, a song can sound major in the verse and minor in the chorus without leaving the key signature. That is also why key detectors report “C major or A minor” style pairs.
How many keys are there in music?
There are 12 different tonics in Western music, and each can be major or minor, which makes 24 keys that sound different. On paper there are 30 key signature names (15 major, 15 minor), because six pairs of names are enharmonic twins that sound the same: F♯ major = G♭ major, C♯ major = D♭ major and B major = C♭ major, plus their relative minors.
When a song moves from one key to another partway through, that is a modulation, or key change. The classic pop version lifts the last chorus by one or two semitones.
Why the key matters for singers
The key sets where the melody sits in your voice. A song written for a tenor in E major may sit too high for a baritone, who can sing the same song comfortably in C or D. Nothing about the song changes except its key. What key should I sing in? gives the method, starting from your notes in the vocal range test. If a song strains your top notes, see song too high; if it buries your voice, song too low.
Changing the key of a recording takes one slider: the online key changer moves a song by semitones without changing its speed, and the karaoke pitch changer does it for backing tracks. For chords and sheet music, use transpose music online. Count the steps with the semitones-to-change-key table or the semitone calculator; the full walkthroughs are how to change the key of a song and how to transpose a song.
How do you know the key of a song?
Three quick clues: the chord the song ends on, the key signature in the sheet music, and the one note that fits over the whole song when you hum it. The song key finder does it from an audio file; in our tests it named 24 of 24 synthetic major and minor keys correctly (how we test). The manual method is in how to find the key of a song.
Frequently asked questions
What does song key mean?
It means the tonic (home note) and the scale a song uses. “In A minor” means A is home and the notes come from the A minor scale. See Key (music) for the formal definition.
What is a key in singing?
The same thing as in any music, but singers feel it as range: a higher key moves every note of the melody up. Singers often ask for a song in a lower or higher key to fit their voice.
Is the key of a song the same as its pitch?
No. Pitch is how high one note sounds. The key is the set of notes a song uses around a tonic. Raising every pitch by the same amount changes the key.
How do keys work in music?
The tonic sounds like home and the other scale notes lead towards or away from it. Chords built from the scale (I, IV and V are the most common) keep the song in the key.
What is the difference between C major and A minor?
They share the same notes and key signature (no sharps or flats) but have different tonics: C in C major, A in A minor. They are relative keys.
Can a song have more than one key?
Yes. A key change inside a song is called a modulation; many pop songs raise the final chorus by one or two semitones. More theory is in our pitch and key guides, and every tool is on all pitch tools. Start from the online pitch changer.