There are 12 note names in Western music, and they repeat endlessly up and down the pitch spectrum. The notes are C, C#/Db, D, D#/Eb, E, F, F#/Gb, G, G#/Ab, A, A#/Bb, and B. After B comes C again, but an octave higher or lower.
The 12 notes make up the chromatic scale, the complete set of pitches used in Western music. Each of these notes corresponds to a specific frequency. The spacing between adjacent notes is always the same frequency ratio—about 5.9% apart—so that the intervals between notes feel and sound consistent, no matter which octave you’re in.
Understanding the Chromatic Scale
The chromatic scale is built from semitones—the smallest pitch intervals in Western music. A semitone (also called a half step) is the distance from one note to the very next note. C to C# is one semitone. C# to D is one semitone. There are no notes in between.
Many people find it helpful to memorize the chromatic scale ascending: C, C#, D, D#, E, F, F#, G, G#, A, A#, B, then C again. Descending: C, B, Bb, A, Ab, G, Gb, F, E, Eb, D, Db, C.
Within the chromatic scale, certain note relationships form patterns that Western music relies on. The major scale (do, re, mi, fa, sol, la, ti, do) is a subset of these 12 notes, using seven of them and leaving out five. Different modes and scales select different subsets, but they all come from the same 12-note foundation.
Sharps, Flats, and Natural Notes
The white keys on a piano are the natural notes: C, D, E, F, G, A, B. The black keys are the sharps and flats. The black key between C and D is both C# (C sharp—one semitone higher than C) and Db (D flat—one semitone lower than D). They’re the same pitch, but the name depends on context and which scale or key you’re in.
When you raise a note by a semitone, you add a sharp symbol (#). When you lower a note by a semitone, you add a flat symbol (b). When a note has been raised or lowered but the notation wants to revert it to its natural state, you add a natural symbol (♮).
Understanding the note names and their frequencies helps you tune instruments, write music, and communicate with other musicians.
Octaves and Pitch Notation
An octave is the interval from one note to the same note an octave higher or lower. When you go up an octave, the frequency doubles. When you go down an octave, the frequency halves.
Scientists and musicians use a notation system called scientific pitch notation to distinguish notes in different octaves. Middle C (the C near the middle of a piano keyboard) is written C4. The A note that orchestras use for tuning is A4 (440 Hz). The C one octave above middle C is C5. The C one octave below middle C is C3.
This notation eliminates confusion. When someone says “tune to A4,” you know exactly which A they mean—the one at 440 Hz, not a higher or lower A. Each note name (C, C#, D, etc.) has multiple Hertz values, one for each octave. Learning scientific pitch notation helps you identify and communicate about specific frequencies.
Reading Note Names on a Staff
In written music, notes are placed on a five-line staff. The position of the note on the staff tells you which note it is. Different clefs (treble, bass, alto) assign different note names to different staff positions.
In treble clef, which is used for higher-pitched instruments and voices, the lines from bottom to top are E, G, B, D, F (remembered as “Every Good Boy Does Fine”). The spaces between the lines are F, A, C, E (reading upward).
In bass clef, which is used for lower-pitched instruments, the lines are G, B, D, F, A, and the spaces are A, C, E, G.
Learning to read note names on a staff takes practice, but the system is logical. Each line and space corresponds to a specific note name, and note names repeat in a predictable pattern as you move up and down the staff.
Frequently Asked Questions
Why are there sharps and flats if they’re the same pitch?
Sharps and flats are enharmonic equivalents—they sound the same but have different names depending on context. In the key of C major, you’d call the black key between C and D a C#. In the key of Db major, you’d call it a Db. The name depends on which scale you’re in and the direction you’re moving. Using the right name keeps musical notation clear and readable.
What comes after B in the chromatic scale?
C comes after B. The notes repeat in an endless cycle. Going up: B, C, C#, D… Going down: C, B, Bb, A… The octave number changes when you cross from B to C (or from C down to B), so C4 is higher than B3, and C3 is lower than B2.
How many octaves are there on a piano?
A standard 88-key piano has about 7.3 octaves. It starts at A0 and ends at C8. Most musical activity happens in the middle octaves—C2 to C6—which span from very low bass to very high treble.
Vincent is a pitch detection and vocal analysis writer at OnlinePitchDetector. He focuses on pitch recognition, vocal frequency analysis, singing tools, and real-time audio testing for singers, musicians, producers, and beginners.