Music interval calculator

Two notes → interval. Pick a lower and an upper note. The calculator names the interval (for example major third), gives its short symbol (M3), the number of half steps, the inversion and whether it's consonant or dissonant. Tick the compound option to put the upper note one more octave up and get ninths, tenths and beyond.

Note + interval → note. Pick a starting note, an interval and a direction. The tool returns the correctly spelled target: a major third above E♭ is G, a minor third above C♯ is E, and a diminished seventh above C is B𝄫 (double flat), not A, because interval spelling depends on letter names, not just on keys.

Half steps	Interval	Symbol	Example from C
0	Perfect unison	P1	C–C
1	Minor second	m2	C–D♭
2	Major second	M2	C–D
3	Minor third	m3	C–E♭
4	Major third	M3	C–E
5	Perfect fourth	P4	C–F
6	Augmented 4th / diminished 5th (tritone)	A4 / d5	C–F♯ / C–G♭
7	Perfect fifth	P5	C–G
8	Minor sixth	m6	C–A♭
9	Major sixth	M6	C–A
10	Minor seventh	m7	C–B♭
11	Major seventh	M7	C–B
12	Perfect octave	P8	C–C'

The same chart is built into the tool; click any example to hear it.

To invert an interval, move the lower note up an octave. The numbers always add up to 9 and the quality flips: major becomes minor, augmented becomes diminished, and perfect stays perfect. A major third (C–E) inverts to a minor sixth (E–C); a perfect fourth inverts to a perfect fifth.

The calculator also labels how the interval sounds in traditional theory:

• Perfect consonance: unison, octave and fifth. The fourth is consonant too, but treated as a dissonance above the bass in classical harmony.
• Imperfect consonance: major and minor thirds and sixths.
• Dissonance: seconds, sevenths and every augmented or diminished interval, even when it sounds like a consonant one on the piano (an augmented second sounds like a minor third).

The Ear training box plays a random interval and you pick its name. Start with the Basic set (M2, m3, M3, P4, P5, P8) and move on to All 12 when you're ready. Choose Melodic to hear the two notes one after the other, or Harmonic to hear them together, which is harder. The score and your current streak are shown as you go.

A classic trick is to link each interval to the start of a song you know: many people hear a perfect fourth as Here Comes the Bride and a perfect fifth as the opening of the Star Wars theme. Use whichever songs work for you. Everything runs in your browser, so the quiz works offline once the page has loaded.