A scale degree is the numbered position of a note within a scale (1 through 7), measured from the tonic, with each degree carrying a name (tonic, supertonic, mediant, subdominant, dominant, submediant, leading tone) and a functional role in melody and harmony.
A scale degree tells you where a note sits inside its scale, counted up from the tonic. Degree 1 is the tonic, 2 is the supertonic, 3 is the mediant, 4 is the subdominant, 5 is the dominant, 6 is the submediant, and 7 is the leading tone (or subtonic when it sits a whole step below tonic in natural minor). In notation you'll usually see these written with a caret over the number.
Here's the big idea. Scale degrees are relative, not fixed pitches. In C major, the dominant is G; in D major, it's A. That relativity is exactly why scale degrees power so much of the course. They name melody notes regardless of key, they tell you which triad gets which Roman numeral (the chord built on scale degree 3 is the mediant chord, iii in major or III in minor), and they explain why a melody transposed to a new key still sounds like the same tune. The intervals between scale degrees stay constant even when the pitches change.
Scale degrees are the connective tissue between melody and harmony in the CED. In Unit 2 (Topic 2.10, Melodic Transposition), learning objective AP Music Theory 2.10.A asks you to identify features of melody in performed and notated music. Per PIT-3.C.6, transposition moves a melody to a new pitch level while keeping its intervallic content, which only makes sense if you think in scale degrees rather than letter names. A C major melody moved up a whole step lands in D major, but every note keeps its scale degree.
In Unit 5 (Topic 5.4, The iii (III) Chord), learning objective AP Music Theory 5.4.A asks you to identify and describe harmonic function and progression. Every chord's identity starts with the scale degree it's built on. The mediant triad sits on scale degree 3, and per PIT-2.J.3 it's rare in 18th-century-style progressions, though III in minor often stands in for the relative major key. If you can't instantly map scale degree numbers to chord names and functions, Units 4 through 7 fall apart.
Keep studying AP Music Theory Unit 2
Visual cheatsheet
view galleryTonic (Units 1-2)
The tonic is scale degree 1 and the reference point for every other degree. All the names (supertonic, mediant, dominant) describe a note's relationship to tonic, so scale degrees are really a map of gravitational pull toward home.
Chord Function (Units 4-5)
Each diatonic triad takes its name and Roman numeral from the scale degree it's built on. The chord on degree 5 is the dominant (V), the chord on degree 3 is the mediant (iii or III), and a chord's function in a progression flows directly from its root's scale degree.
Melodic Transposition (Unit 2)
Transposition works because scale degrees travel with the melody. Move a tune from C major to D major and every pitch changes, but degree 3 is still degree 3. Thinking in scale degrees is how you transpose without recalculating every interval.
Dominant (Units 4-5)
Scale degree 5 sits a perfect fifth above tonic, and the chord built on it creates the strongest pull back to degree 1. The dominant is the clearest example of a scale degree's name describing its job.
Scale degrees show up constantly in multiple choice, in both melodic and harmonic contexts. Expect stems like "What scale degree does the mediant chord represent in a major scale?" or questions asking which scale degrees a chord contains in first inversion (the mediant in first inversion stacks degrees 3, 5, and 7 with degree 5 in the bass). Harmonic dictation and part-writing questions also track scale degrees in individual voices, like identifying where the soprano lands on each chord of an 8-7-6-5 melodic descent. No released FRQ uses the phrase "scale degree" as the question itself, but sight-singing, melodic dictation, and the part-writing FRQs all assume you can think in scale degrees automatically. The skill being tested is translation: number to pitch, pitch to number, and number to chord function, fast and in any key.
Scale degrees label single notes (Arabic numerals with carets, like degree 3). Roman numerals label entire chords built on those degrees (iii or III). They're linked because the chord takes its numeral from its root's scale degree, but "scale degree 3" is one pitch while "iii" is a three-note triad with a quality and a function. Mixing them up will cost you on part-writing and analysis questions.
Scale degrees number the notes of a scale 1 through 7 from the tonic, and each has a name: tonic, supertonic, mediant, subdominant, dominant, submediant, and leading tone.
Scale degrees are relative to the key, so the dominant is G in C major but A in D major, which is exactly why transposed melodies keep their identity (PIT-3.C.6).
Every diatonic chord is named after the scale degree of its root, so the mediant chord is the triad built on scale degree 3.
In minor keys, the III chord built on scale degree 3 often represents the relative major key, while the mediant triad is rare in 18th-century-style progressions (PIT-2.J.3).
Degree 7 is called the leading tone when it sits a half step below tonic and pulls upward to resolve; in natural minor it sits a whole step below and is called the subtonic.
On the exam, you need to convert between scale degree numbers, actual pitches, and chord Roman numerals in any key without stopping to count.
A scale degree is a note's numbered position within a scale, counted 1 through 7 from the tonic. Each degree has a name and a functional role, like degree 5 (the dominant) pulling back toward degree 1 (the tonic).
No. Scale degrees are Arabic numbers for individual notes, while Roman numerals label whole chords built on those notes. The chord on scale degree 3 gets the Roman numeral iii in major (III in minor), but degree 3 by itself is just one pitch.
No, and that's the whole point. Per the CED (PIT-3.C.6), transposing a C major melody up a whole step puts it in D major with all new pitches, but every note keeps its original scale degree because the intervallic content stays the same.
Tonic (1), supertonic (2), mediant (3), subdominant (4), dominant (5), submediant (6), and leading tone (7). When degree 7 sits a whole step below tonic, as in natural minor, it's called the subtonic instead.
Scale degree 3, which is why it's labeled iii in major and III in minor. The mediant triad contains degrees 3, 5, and 7, and in minor keys III often represents the relative major key (PIT-2.J.3).
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