Octave
A octave is 12 half steps, written P8. From C it reaches C. Hear it one note after the other, then together.
What it sounds like
Twelve half steps: the same note, higher. The frequency doubles, so the two notes blend completely.
Men and women singing "the same" melody are usually an octave apart. On guitar, octave shapes are two strings and two frets apart.
How to recognise a octave by ear
Sing do to the higher do. Played together, the two notes merge so fully that many listeners hear only one note. When men and women sing the same tune together, they are singing in octaves.
Add an octave and a octave becomes a double octave (24 half steps), two strings and four frets apart on guitar. Intervals bigger than an octave are called compound intervals; they keep the character of the smaller interval but sound more open.
On guitar there are two octave shapes worth memorising. From a note on the low E or A string, the octave is two strings higher and two frets up. From the D or G string it is two strings higher and three frets up, because the B string is tuned a half step lower than the pattern. On piano an octave is eight white keys from one C to the next, which is a full hand stretch from thumb to little finger; practise it with those two fingers only until the jump feels automatic.
A octave from every note
The letter name moves up 7 letters (the same letter) and the distance is always 12 half steps.
| From | Up a octave | |
|---|---|---|
| C | C | |
| D♭ | D♭ | |
| D | D | |
| E♭ | E♭ | |
| E | E | |
| F | F | |
| F♯ | F♯ | |
| G | G | |
| A♭ | A♭ | |
| A | A | |
| B♭ | B♭ | |
| B | B |
Finding it on guitar
12 frets is a long stretch, so guitarists usually play a octave across strings: on the next higher string it's 7 frets up from the starting note, and between the G and B strings add one more. The diagram starts from A on the low E string.
Other intervals
- minor second
- major second
- minor third
- major third
- perfect fourth
- tritone
- perfect fifth
- minor sixth
- major sixth
- minor seventh
- major seventh
Octave: questions
How many half steps is a octave?
12. An octave is 12 half steps, the same note name higher.
What is a octave above C?
C. Above G it is G, above D it is D.
Is a octave consonant or dissonant?
Perfect consonance. Twelve half steps: the same note, higher.
Spellings computed from letter names and half steps, and checked against both. Updated September 2026.