Music Interval Calculator — name & semitones
Find the interval between two notes — its name and semitone count — or get the note a given interval away.
🔒 Runs entirely in your browser. Your input and output are never sent to a server or stored — fully private.
About this tool
The interval calculator names the distance between any two notes — a major third or a perfect fifth, say — and gives its size in semitones, or works the other way to find the note a chosen interval above or below a starting pitch. It is a quick helper for ear training, harmony homework or building chords by hand. Everything is worked out in your browser.
Frequently asked questions
What is a musical interval?
An interval is the pitch distance between two notes, described by a number and a quality — a minor third (three semitones) or a perfect fifth (seven semitones), for example. Intervals are the building blocks of chords, melodies and scales.
How many semitones is a perfect fifth?
A perfect fifth spans seven semitones — C up to G, for instance. The calculator shows the semitone count for any interval, which makes it easy to transpose a part or build a chord with the right spacing.
Why are an augmented 4th and a diminished 5th different names for the same sound?
Because interval names describe how the notes are spelled, not just how far apart they sound. C to F# spans four letter names (C-D-E-F) so it is a fourth; C to Gb spans five (C-D-E-F-G) so it is a fifth. On a piano both are six semitones and sound identical — they are enharmonic. Which spelling is correct depends on where the music is going: F# usually resolves upward, Gb downward, and choosing the right one makes a score far easier to read.
What is an inverted interval?
Move the lower note up an octave (or the upper note down) and you get the inversion. The two sizes always add up to nine — a third inverts to a sixth, a fourth to a fifth — and the quality flips: major becomes minor, augmented becomes diminished, while perfect stays perfect. It is worth knowing because it lets you name a wide interval instantly by inverting it into something you recognise.
How do intervals help when transposing for an instrument?
Transposing instruments are defined by an interval. A B-flat trumpet sounds a major 2nd below what is written, so the part must be written a major 2nd higher than concert pitch; an E-flat alto saxophone sounds a major 6th below. Once you think in intervals rather than counting semitones, writing or reading a transposed part becomes a single consistent shift, and our transpose tool applies the same shift to a whole passage.