Interval Calculator
Distance Between Two Notes, Measured in Semitones
Every interval in Western music — a third, a fifth, an octave — is really just a count of semitones between two pitches, given a name by convention. This calculator works both directions: identify the interval between two notes you already have, or start from one note and transpose it by a named interval to find the other.
The Formula
Semitone Distance = |Semitone(Note 2) − Semitone(Note 1)|
Transposed Note = Start Note ± Interval (in semitones)
Transposed Note = Start Note ± Interval (in semitones)
Each note is first converted to an absolute semitone count (octave × 12, plus the note's position within the octave). The interval name is then read from the remainder after dividing the semitone distance by 12, with any full octaves reported separately.
Where This Calculation Matters
- Ear training — identifying the interval between two notes by name is a core skill tested in music theory and ear-training courses.
- Transposing melodies — arrangers move a melody up or down by a fixed interval (a major third for a key change, an octave for a different instrument's range) without changing its shape.
- Harmony and voicing — knowing the exact interval between chord tones determines whether a voicing sounds consonant (thirds, fifths, sixths) or dissonant (seconds, tritones, sevenths).
- Instrument tuning checks — comparing two strings or notes against their expected interval catches tuning errors an ear alone might miss.
| Semitones | Interval name |
|---|---|
| 0 | Perfect Unison |
| 1 | Minor 2nd |
| 2 | Major 2nd |
| 3 | Minor 3rd |
| 4 | Major 3rd |
| 5 | Perfect 4th |
| 6 | Tritone |
| 7 | Perfect 5th |
| 8 | Minor 6th |
| 9 | Major 6th |
| 10 | Minor 7th |
| 11 | Major 7th |
| 12 | Perfect Octave |
How to Use This Calculator
- Choose a mode: identify the interval between two notes, or transpose a note by an interval.
- In identify mode, enter both notes and their octave numbers.
- In transpose mode, enter the starting note and octave, the interval name (such as "major 3rd" or "p5"), and a direction — up or down.
- Select Calculate to get the interval name and semitone distance, or the resulting transposed note.
Related Calculations
Build a full progression from a root note and scale with the Chord Progression Calculator, or find the exact frequency of any note with the Note Frequency Calculator.