Scales, Keys & Modes

Leading Tone

Definition

The leading tone is the seventh degree of a scale when it lies a half step below the tonic: B in C major, G♯ in A minor. Its strong pull upward makes the tonic feel like a destination.

The leading tone is scale degree 7 when it sits a half step below the tonic: B in C major, G♯ in A minor. British musicians usually call it the leading note. In major and do-based minor solfège it is ti; in la-based minor it is si.

Two treble-clef examples in 4/4. C major: quarter notes C D E F G A B C, numbered 1 to 8, with the words leading tone written under B. A harmonic minor: A B C D E F G-sharp A, numbered 1 to 8, with leading tone under G-sharp. — The leading tone is degree 7, a half step below the tonic: B in C major and G♯ in A minor, where the 7th is raised as in harmonic minor.

Why it leads

A note a half step away from a stable note tends to move to it, and the leading tone is a half step below the most stable note of all. Play C D E F G A B in C major and stop: the B hangs in the air until you play C. That pull is a large part of why a major key feels so clearly centered.

Two grand-staff examples in 4/4, two bars each. Both start with right-hand quarter notes E F G A over left-hand half notes C and F. The first ends with a whole-note B over a bass G. The second ends with a half-note B and a half-note C over bass notes G and C. — The same original phrase in C major, twice. The first stops on the leading tone, B, over a G in the bass, and sounds unfinished. The second lets B rise to C over a C bass, and the phrase comes home.

In major and minor keys

Every major scale has a leading tone. The natural minor scale does not: its 7th degree is a whole step below the tonic (G in A minor), and a 7th in that position is called the subtonic. To get a leading tone, minor keys raise the 7th with an accidental, G♯ in A minor, as the harmonic and melodic minor scales do. That accidental is one of the surest signs that a piece is in a minor key.

In chords

The leading tone is the 3rd of the dominant chord (G B D in C major) and the root of the diminished triad on degree 7 (B D F, written vii°). In a V7–I cadence it rises to the tonic while the chord's 7th falls, and in traditional voice leading a leading tone in the top or bottom voice is expected to resolve up. That is also why it is not doubled in four-part writing: two leading tones would both need to rise to the same note and make parallel octaves.

The C major scale numbered by degree, with the leading tone, B, in coral, a half step below the top C.

Leading tones elsewhere

Any note a half step below a target can act as a leading tone to it. A secondary dominant creates a temporary leading tone to a chord other than the tonic: in C major, the F♯ of D7 leads up to G. When a new leading tone appears and stays, the music has usually modulated; Hear the Raised Note Before Five trains you to hear one.

Common questions

What is the difference between a leading tone and a subtonic?

Both are the 7th degree. The leading tone is a half step below the tonic (B in C major, G♯ in A minor) and pulls up to it; the subtonic is a whole step below (G in A natural minor) and has much less pull.

Is it called leading tone or leading note?

Both. Leading tone is the usual American term and leading note the usual British one; they mean the same thing.