MusicReasonScales, Keys, Intervals, and Notation
Build and hear an interval from a root
Choose a root and an interval. This tool spells the target note, shows the semitone count, and plays both notes after a click, so you can build an interval as a deliberate choice rather than asking what an existing note pair means.
Answer and Play
Want to learn more? Intervals: Number, Quality, Direction & Inversion
Understand
An interval's number and quality are independent facts: two intervals with the same semitone count can still be genuinely different intervals depending on spelling, and this tool always shows both together rather than reducing an interval to a single number. Playback here uses 12-tone equal temperament exclusively; a just-intonation or other temperament comparison is a separate, more specialized job this tool does not attempt.
Worked examples
C4 ascending Perfect 5th gives G4. C4 descending minor 3rd gives A3, not A-sharp3 or any other enharmonic equivalent, since a minor 3rd below C always lands two letters down (C, B, A) with whatever accidental reaches the correct pitch class.
Method and limitations
The target note's letter is chosen by moving the interval's diatonic number of letter steps from the root (wrapping through the seven-letter cycle for a compound interval), then spelled with whatever accidental reaches the interval's exact target pitch class. Playback requires your gesture and stops cleanly; it never begins automatically. A compound interval is shown alongside its simple equivalent so the relationship to a more familiar simple interval stays visible.