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Interval calculator
Pick two notes to name the interval between them, or a note and an interval to find the other note.
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How intervals are named
An interval has a number and a quality. The number counts letter names, including both ends: C to E is a third (C, D, E), C to G a fifth. The quality depends on the exact number of half steps: unisons, fourths, fifths and octaves are perfect; seconds, thirds, sixths and sevenths are major or minor. One half step more than major or perfect is augmented; one less than minor or perfect is diminished.
That's why C to F♯ (an augmented fourth) and C to G♭ (a diminished fifth) are different intervals even though both are six half steps: the letters are different.
Inversions and compound intervals
Inverting an interval (moving the lower note up an octave) turns its number into 9 minus the number, and swaps major with minor and augmented with diminished; perfect stays perfect. A major third inverts to a minor sixth. Intervals larger than an octave are compound: a major ninth is a major second plus an octave.
Intervals from C
| Interval | Short name | Semitones | From C |
|---|---|---|---|
| perfect unison | P1 | 0 | C – C |
| minor second | m2 | 1 | C – D♭ |
| major second | M2 | 2 | C – D |
| minor third | m3 | 3 | C – E♭ |
| major third | M3 | 4 | C – E |
| perfect fourth | P4 | 5 | C – F |
| augmented fourth | A4 | 6 | C – F♯ |
| diminished fifth | d5 | 6 | C – G♭ |
| perfect fifth | P5 | 7 | C – G |
| minor sixth | m6 | 8 | C – A♭ |
| major sixth | M6 | 9 | C – A |
| minor seventh | m7 | 10 | C – B♭ |
| major seventh | M7 | 11 | C – B |
| perfect octave | P8 | 12 | C – C |
Frequently asked questions
How many half steps are in a perfect fifth?
Seven: C to G, for example.
What is a tritone?
An interval of three whole steps (six half steps), half an octave: the augmented fourth (C to F♯) or the diminished fifth (C to G♭).
Is C to D♯ a minor third?
No: C to D♯ is an augmented second. It has three half steps, like the minor third C to E♭, but it spans only two letters.