Music Interval Calculator — Semitones & Interval Names
Select two notes from the chromatic scale and instantly get the ascending interval in semitones, the traditional interval name (e.g. Major 3rd, Perfect 5th, Tritone), its abbreviation, the descending complement, and whether the interval is consonant or dissonant.
First note
Second note
Major 3rd (M3)
- 1
Semitone of C
0Chromatic scale position: C = 0, C♯ = 1, D = 2, … B = 11. - 2
Semitone of E
4 - 3
Ascending interval
(4 − 0 + 12) mod 12 = 4
How does this calculator work?
Semitone distance = (note2 − note1 + 12) mod 12, counting upward through the chromatic scale (C=0, C♯=1, … B=11). 4 semitones = Major 3rd; 7 = Perfect 5th; 6 = Tritone. The descending interval is 12 minus the ascending distance. Select two notes to get the interval name, abbreviation, and consonance classification.
Formula
How this is calculated
The Western chromatic scale divides an octave into 12 equal semitones. Each note is assigned a semitone value from C = 0 through B = 11. The ascending interval from note1 to note2 is (semitone2 − semitone1 + 12) mod 12 — the modulo 12 ensures the result is always a positive number in the range 0–11, counting upward from the first note to the second within the same octave.
Each semitone distance maps to a traditional 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. The descending interval (12 − ascending) is the complement — the interval you would travel going down from note1 to note2.
Consonance is a perceptual classification: intervals with simple frequency ratios (unison, thirds, fourths, fifths, sixths) sound stable and are considered consonant; seconds, sevenths, and the tritone are dissonant and create harmonic tension. This classification reflects common-practice Western harmony and may differ slightly in other musical traditions.
Frequently asked questions
A semitone (half step) is the smallest interval in Western music — one step on the chromatic scale, e.g. C to C♯. A whole tone (whole step) is two semitones, e.g. C to D. The major scale pattern of W-W-H-W-W-W-H (whole/half steps) uses both.
The tritone exactly bisects the octave into two equal halves. Depending on context it is notated as an augmented fourth (A4, e.g. C to F♯) or a diminished fifth (d5, e.g. C to G♭) — both span 6 semitones but are spelled differently on the staff. It is the most dissonant interval in tonal harmony.
No — this calculator works within one octave (0–11 semitones). It tells you the interval class regardless of which octave each note is in. C4 to E5 is a Major 10th (= Major 3rd + octave), but its interval class is a Major 3rd (4 semitones). For compound intervals (spanning more than one octave), add 12 semitones per additional octave.
Also known as
TG we-Calculate Editorial Team. (2026). Music Interval Calculator — Semitones & Interval Names [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/music-interval-calculator
TG we-Calculate Editorial Team. "Music Interval Calculator — Semitones & Interval Names." TG we-Calculate. 2026. https://we-calculate.com/calculator/music-interval-calculator.
TG we-Calculate Editorial Team, "Music Interval Calculator — Semitones & Interval Names," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/music-interval-calculator
@misc{wecalculate_music_interval_calculator, title = {Music Interval Calculator — Semitones & Interval Names}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/music-interval-calculator}}, year = {2026}, note = {TG we-Calculate} }
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