Small steps

The SEMITONE (half step) is the smallest distance on the piano: from any key to the very next one, black keys included. E to F is a semitone; C to C# is a semitone.

A WHOLE TONE (whole step) is two semitones: skip exactly one key. F to G is a whole tone (F# sits in between). E to F# is also a whole tone.

These two steps are the atoms of music: every scale and chord you will ever learn is a recipe of semitones and whole tones. Count keys — never skip the black ones.

semitone = next key · whole tone = 2 semitones

E→F: a semitone (neighbours). G→A: a whole tone (G# in between).

Practise this in the trainer — it opens with this lesson the first time the concept comes up.