Half Steps and Whole Steps

On a piano, a half step is the distance from any key to the very next key, white or black, with nothing between them. A whole step skips one key in between, so it equals two half steps stacked. The keyboard looks even, with white keys in a repeating row, but it is not evenly spaced in pitch. Between E and F, and between B and C, there is no black key at all, so those pairs are already a half step apart. Everywhere else between white keys, a black key sits in the middle, making that gap a whole step. That uneven pattern of half steps and whole steps is exactly what gives the major scale its sound.

On the staff, you count the same way but by letter name and line-or-space movement rather than by looking for black keys. Moving E to F is a half step because they are adjacent letters with no note between them; moving F to G is a whole step because F sharp sits between them. Accidentals shift this: B to C sharp adds an extra half step on top of the normal B-to-C half step, making it a whole step overall; D to E flat is a half step, since E flat sits right next to D; G to A is a whole step, matching the usual gap between those two letters.

Half steps split into two kinds. A diatonic half step moves between two different letter names, like E to F. A chromatic half step stays on the same letter and only adds an accidental, like C to C sharp. This distinction becomes essential once you build major scales, since the correct scale spelling depends on using one letter of each name in order, which means choosing diatonic half steps in the right places rather than chromatic ones.