MusicReasonScales, Keys, Intervals, and Notation
What interval is between these two notes?
Enter two spelled notes with octaves. This tool names the interval between them, including direction and quality, using their actual notation, not just a raw semitone count.
Answer
Want to learn more? Intervals: Number, Quality, Direction & Inversion
Understand
Notation is required evidence, not decoration: C to F-sharp and C to G-flat sound identical (six semitones) but are different intervals on paper. Because F is a fourth letter above C while G is a fifth, the first is an Augmented 4th and the second is a Diminished 5th, even though a bare semitone calculator would report both as "6 semitones" with no way to distinguish them. This tool only accepts fully spelled input for exactly that reason: a pitch-class pair alone cannot produce a defensible interval name.
Worked examples
C4 to E4 is a Major 3rd (4 semitones, a diatonic 3rd). C4 to F-sharp4 is an Augmented 4th (6 semitones, a diatonic 4th, one semitone wider than the perfect 4th baseline). C5 down to E4 is a descending minor 6th (8 semitones, a diatonic 6th one semitone narrower than the major 6th baseline).
Method and limitations
The diatonic number counts letter names inclusively between the two notes, extending past an octave for a compound interval. Quality compares the actual semitone distance for that diatonic number against the major-scale baseline: unison, 4th, 5th, and octave-class numbers are judged against a Perfect baseline (Augmented above, Diminished below); 2nd, 3rd, 6th, and 7th-class numbers are judged against a Major baseline (Minor one semitone below, Augmented one above). Unordered mode reports the interval without regard to which note came first; ordered mode preserves and reports direction.