Music tools
Interval calculator
Name the interval between two notes, or build a note a chosen interval above or below a root. Everything runs in your browser.
Name an interval
From the first note up to the second.
Build a note
A chosen interval above or below a root.
How it works
An interval is the distance in pitch between two notes, named by a number and a quality - a third, a fifth, major, minor, perfect, and so on. Enter two note names and the calculator works out the interval between them, counting the ascending distance from the first note up to the second. It uses the letter names as well as the pitch, so it tells a major third apart from a diminished fourth even though both span four semitones.
Switch to build mode to go the other way: pick a starting note and an interval, choose up or down, and get the resulting note spelled correctly. It is handy for harmony homework, transposing by ear, or just checking your theory. Everything is computed in your browser.
Example. From C up to G is a perfect fifth (seven semitones); from C up to E is a major third. In build mode, a major sixth above D gives B, and a perfect fourth below A gives E.
FAQ
How is an interval named?
By two parts: a number from the letter distance (C to E spans three letters, so a third) and a quality (major, minor, perfect, augmented, or diminished) from the exact number of semitones. Together they name the interval, such as "major third" or "perfect fifth".
Why does spelling matter for intervals?
Notes that sound the same can be different intervals. C to D# and C to Eb are both four semitones, but the first is an augmented second and the second is a minor third, because the letter distance differs. Using note names rather than just pitches keeps the naming correct.
Can I build a note from an interval?
Yes. In build mode you choose a root note, an interval, and a direction (up or down), and the tool returns the note that far away, spelled with the right letter and accidental.
Does it run offline?
Yes. The interval math is done in your browser with no server calls, so it works offline and nothing is uploaded.