Fundamentals
Understanding Musical Notes
Music uses seven letter names that repeat for ever, five more notes squeezed between them, and a naming system that gives many of those twelve two names apiece — and each of those three facts has a reason.
Beginner · 4 sections
Why the Letters Stop at G
Play the first chip and count how many sounds go by before it stops. Then play the second, which carries straight on from it. Somewhere in the second you will feel that you have been here before.
| Position | Name | What happens next | |
|---|---|---|---|
| 1 | C | The run begins | |
| 2 | D | ||
| 3 | E | ||
| 4 | F | ||
| 5 | G | The last new letter | |
| 6 | A | Back to the start of the alphabet | |
| 7 | B | ||
| 8 | C | The same name as position 1, and near enough the same sound |
A note is a sound of a definite pitch, together with the name that identifies it wherever it occurs.
The letters run A to G and then start again, and this is the first thing that confuses people coming to music from anything else: an alphabet that stops after seven letters looks like an oversight. It is not. The eighth sound in the run above is so nearly the same as the first that giving it a new name would be actively misleading — a singer asked for it would produce something a listener would call the same note.
So the naming system is honest about a fact of hearing. There are only seven names because, after seven, the ear says you have arrived back where you started. Everything above and below is the same seven names again, at a different height.
That is why a keyboard looks like one picture repeated. It is not decoration, and it is not there to help beginners: it is the shape of the thing being named.
Fact
The eighth note of the run sounds like the first, which is why the names run out after seven rather than after twenty-six.
Convention
Letters are one tradition among several. Much of Europe and Latin America names the same notes do, re, mi, fa, sol, la, si, and German usage writes H where English writes B natural.
You already know this
Where this goes
In real music
- Do-Re-Mi, Richard Rodgers — the whole song is the seven names in order, and it ends by arriving back at the first
Find a C on your instrument and play upwards, naming each note aloud, until you reach the next C. You should say seven names and arrive at the eighth. Do it again from a different starting letter and confirm that the count does not change.
Check 1
This run starts on G. What is the fifth note you hear?
Why the Pattern Comes Back Round
Two pairs, each sounded together. One pair sounds like one thing at two heights. The other sounds like two things.
- What makes them blend
- The upper note vibrates exactly twice as fast as the lower one
- The ratio
- 2 to 1 — the simplest relationship two pitches can have, short of being identical
- The consequence
- They take the same letter name, and the names repeat every octave
An octave is the distance between a note and the next note of the same name, whose sound is produced by exactly twice the rate of vibration.
This is the one fact in this lesson that is physics rather than custom. Double the frequency of a sound and you get a pitch so closely related to the original that every musical culture which has looked into the matter has treated the two as versions of the same thing. It is not a Western convention, and it is not learned: it is how hearing works.
Everything else follows from it. The names repeat every octave because the sound repeats every octave. A keyboard is built from an octave-sized unit stamped over and over. A guitarist finds the same note twelve frets up. Men and women singing "the same" melody are usually an octave apart and nobody notices, because there is nothing to notice.
It also fixes what a letter name means. "C" does not name one sound — it names a whole column of them, spread across the range of hearing, each double the one below. When precision matters, a number is added: is middle C, the octave above it.
Fact
An octave is a frequency ratio of exactly 2 to 1. If is 440 hertz, the above it is 880.
Fact
Two notes an octave apart share a letter name, which is why the naming system has to repeat and cannot simply run on.
Convention
The octave number changes at C rather than at A, so and the directly above it differ by one in the number despite being neighbours.
You already know this
In real music
- Somewhere Over the Rainbow, Harold Arlen — the first two syllables leap an exact octave, which is why the opening sounds so open
See also
Play a note, then find the same letter above and below it on your instrument, and play all three in turn. On a keyboard they are the same key position one picture along; on a guitar, twelve frets. Sing along with each and notice how little your voice has to change idea.
Check 1
Two notes, sounded together. Are they an octave apart, or something else?
The Five Notes With No Letter of Their Own
Two climbs from the same note to the same note. The second one uses everything available on the way. Count the sounds in each.
| Step | Note | Has its own letter? | |
|---|---|---|---|
| 1 | Yes | ||
| 2 | No — named from a neighbour | ||
| 3 | Yes | ||
| 4 | No | ||
| 5 | Yes | ||
| 6 | Yes — nothing sits between E and F | ||
| 7 | No | ||
| 8 | Yes | ||
| 9 | No | ||
| 10 | Yes | ||
| 11 | No | ||
| 12 | Yes — and nothing sits between B and C |
A half step is the smallest distance between two notes in this system, and there are twelve of them in an octave. (also called semitone, British and most academic usage)
The seven letters are not evenly spaced, which is the thing the table above is really showing. Between most pairs of neighbouring letters there is room for another note; between E and F, and between B and C, there is not. That irregularity is not an accident of the keyboard — the keyboard is shaped that way because the notes are.
The five in-between notes are named by pointing at a neighbour and saying which way you went. is C raised by a half step. The same sound is also , D lowered by one. They get borrowed names because the letters were allocated to a seven-note scale long before anyone needed all twelve, and renaming everything afterwards was never going to happen.
Twelve is where it stops, and the twelve are equally spaced. That even spacing is a tuning decision rather than a law of nature — a deliberate compromise that lets every key sound equally usable — but it is the one nearly all Western instruments are built and tuned to.
Fact
There is no note between and , and none between and . Those two pairs are already a half step apart.
Convention
Dividing the octave into twelve equal half steps is equal temperament, a tuning choice adopted so that every key is equally playable. Other traditions divide the octave differently, and earlier European tunings made the twelve unequal on purpose.
Play every note from one C to the next without skipping anything — on a keyboard that means using the black keys, on a guitar every fret. Count as you go. You should sound twelve notes before arriving at the thirteenth, which is the C you started from.
Check 1
Two notes, one after the other. Is there a note available between them?
Why One Sound Has Two Names
Two chips. Whatever you were told they are called, decide first whether there is anything at all to tell apart.
| Written | Read as | Chosen when | |
|---|---|---|---|
| F raised a half step | The music is moving up, or the key already uses sharps | ||
| G lowered a half step | The music is moving down, or the key already uses flats | ||
| E raised a half step — the same sound as F | A scale needs an E of some kind and F is already taken |
Two notes are enharmonic when they sound the same but are written differently — and are one pitch with two spellings.
This looks like a flaw and is in fact the naming system being careful. A written note is not only a sound: it is a sound plus a claim about what that sound is doing. says a note has been raised from F, and a reader expects it to carry on upwards. says a note has been lowered from G, and the expectation is downwards. Same key, different sentence.
The other reason is spelling inside a scale. A scale uses each letter name once, in order, so a scale needing a note between E and F sometimes has to call it even though a keyboard would call that F. Writing F instead would leave the scale with two F-somethings and no E at all, and every chord built from it would be misread.
For a beginner the practical summary is short: if two names land on the same key, they are the same sound, and you have not misunderstood anything. Which spelling to use is a question that arrives later, with keys and scales, and it always has an answer.
Fact
and are the same pitch on a keyboard and on any instrument tuned in equal temperament.
Convention
Which spelling is correct is decided by the key and by the direction of the line, not by the sound. A scale uses each letter once, which is what forces spellings like .
Tendency
A note rising towards its neighbour is usually spelled as a sharp, and one falling towards its neighbour as a flat.
Applies to: Common-practice notation and the popular music that follows it; jazz lead sheets are looser
You already know this
Where this goes
Find the black key between F and G on a keyboard, or the fret between them on a guitar. Play it while saying "F sharp", then play the same note again while saying "G flat". Nothing about the sound changes, and that is the whole of what you need to know today.
Check 1
Which of these is a different sound from the other two?
Key Takeaways
- There are seven letter names because after seven notes the sound repeats, and the naming system follows the ear rather than the alphabet.
- An octave is a doubling of frequency, which is a fact of hearing rather than a Western convention, and it is why the names recur at all.
- Five further notes sit between the letters, making twelve in an octave; the gaps are uneven, with nothing between E and F or between B and C.
- Those five borrow their names from a neighbour, so one sound can be written as a sharp or as a flat depending on where the music is going.
- A letter names a column of notes, not one sound; the number after it says which octave you mean.
Last updated September 22, 2026
Questions
- Why does music use letters instead of numbers?
- Letters name the notes themselves, which do not move; numbers are used too, but for positions inside a scale, where the same number means a different letter in every key. Both systems are in daily use and they answer different questions — "which note" and "which role".
- Are there really only twelve notes in all of music?
- Twelve per octave, in the tuning nearly all Western instruments use. Those twelve then recur in every octave, which is why a piano has 88 keys and not 12. Other traditions divide the octave more finely, and a singer or a violinist can of course sound pitches between the twelve.
- Do I have to memorise all the note names before I can play anything?
- No. Most people learn them by using them, in the order their instrument presents them. Knowing that the letters run A to G and repeat is enough to start; the rest sticks through playing far more reliably than through drilling.
- What does the number after the letter mean?
- It says which octave the note is in, so is middle C and is the C above it. The number changes at C rather than at A, which is why and are neighbours despite the jump in the digit.
Learn this properly
Chapter 2: Pitch, Notes and the Octave