Notes, Octaves, Half Steps and Whole Steps

Music runs on twelve notes. That is the whole alphabet. Every song you have ever sung around a campfire, every gospel chorus and every three-chord protest anthem uses some of those twelve and nothing else.

Seven of them get plain letter names: A, B, C, D, E, F and G. After G you go back to A. The other five live in the gaps and get named after their neighbors, with a sharp sign (#) meaning "a little higher" or a flat sign (b) meaning "a little lower." (Proper printed music uses a special flat symbol. A lowercase b works fine on a chord chart and everyone will know what you mean.)

The keyboard tells you everything

You do not need to play piano to use a piano keyboard as a map. The white keys are the seven letter notes. The black keys are the sharps and flats. Look at the pattern: black keys come in groups of two and three, and that gap pattern is how you find your place.

Find C first. It is always the white key just to the left of a pair of black keys. From there, count up through every key, black and white, and you get the twelve notes in order:

With sharps: C, C#, D, D#, E, F, F#, G, G#, A, A#, B, then C again.
With flats: C, Db, D, Eb, E, F, Gb, G, Ab, A, Bb, B, then C again.

Same twelve keys, two ways to spell the in-between ones. C# and Db are the same key on the piano and the same fret on the guitar. That is called being enharmonic. Which name you use depends on the key of the song, and lesson 2 sorts that out. For now, just know that a guitarist who says "B flat" and a fiddler who says "A sharp" are pointing at the same sound.

Half steps and whole steps

The distance from any key to the very next key, black or white, is a half step. Two half steps make a whole step. Those are the only two building blocks you need for scales.

Here is the quirk that trips everyone up once and then never again. Between most neighboring white keys there is a black key, so C to D is a whole step (C, then C#, then D). But E and F have no black key between them. Neither do B and C. So E to F is a half step and B to C is a half step. There is no E# hiding anywhere in normal country songwriting, and no B# either. (Theory books do use those spellings in rare keys. You can ignore them for years.)

Octaves

Walk up twelve half steps from C and you land on C again, only higher. That distance is an octave. Sing the first two notes of "Over the Rainbow" and you have sung one: the melody jumps from a low note to the same note an octave up.

The physics is tidy. A note is a vibration, measured in hertz (Hz), or cycles per second. The international tuning standard, ISO 16, sets the A above middle C at 440 Hz. The A an octave above it vibrates at 880 Hz. The A an octave below sits at 220 Hz. Up an octave doubles the number, down an octave halves it. Your ear hears those notes as "the same note, higher or lower," which is why men and women can sing the same melody an octave apart and it still sounds like unison.

Middle C, by the way, is about 261.6 Hz. You will see that number on tuner apps and in audio software.

The guitar is a ruler of half steps

On a guitar, every fret is one half step. That makes the neck a very honest ruler. Take the low E string (the thickest one). Play it open, then walk up one fret at a time:

Look at frets 1 and 8. Open E to fret 1 is F, only one fret. Fret 7 is B and fret 8 is C, again only one fret. Those are the two natural half steps, showing up exactly where the keyboard said they would. Fret 12 is E, an octave above the open string. On most guitars that fret has a double dot so you can find it in a dark bar.

This ruler works on every string. The A string (second thickest) starts on A, so fret 2 is B, fret 3 is C, fret 5 is D. If you ever forget a note name, count frets from an open string you know.

Why bother learning names?

Because "play that thing you did, but up a bit" wastes a whole rehearsal. When you can say "start on D and walk down to B," the bass player knows exactly what to do. And every later idea in this module, scales, chords, capo math, is just counting half steps and whole steps from a starting note. Get this part solid and the rest is arithmetic you can do on your fingers.