Octaves can be perfect, augmented or diminished. Below you can see that the number of steps determines the quality of the interval:
Perfect octave, 6 whole steps or 12 half steps:
Augmented octave, 6 1/2 whole steps or 13 half steps:
Diminished octave, 5 1/2 whole steps or 11 half steps:
See I > Intervals for related entries. To learn about go to Tutorials > Intervals.