What is a musical interval?

A musical interval is the pitch distance between two notes, measured in semitones (half-steps). Each interval has a name like "Minor Third" or "Perfect Fifth" that describes both its size and quality.

What does semitone count mean?

One semitone equals one half-step on a piano keyboard — the distance between any key and the immediately adjacent key. A Major Second is 2 semitones, a Perfect Fifth is 7 semitones, and an Octave is 12 semitones.

What are consonant and dissonant intervals?

Consonant intervals sound stable and resolved (Unison, Octave, Perfect Fourth, Perfect Fifth, Major and Minor Thirds and Sixths). Dissonant intervals create tension that wants to resolve (Minor 2nd, Major 2nd, Tritone, Minor 7th, Major 7th).

The Tritone is the interval of 6 semitones — exactly half an octave. It can be spelled as an Augmented Fourth or a Diminished Fifth, and is the most dissonant interval in Western music theory, historically called "diabolus in musica."

How are compound intervals handled?

Any interval larger than 12 semitones is a compound interval — an octave plus a simple interval. For example, 14 semitones is a Compound Major Second (Major Ninth). The calculator shows the full semitone count and labels the compound name.

Music Interval Calculator

Name: Music Interval Calculator
Availability: InStock
Author: Nham Vu

Pick any two notes and instantly see the interval name, semitone count, quality, and consonance rating.

Select Notes

Root Note

261.63 Hz

Direction

Target Note

392.00 Hz

C4 G4

Perfect Fifth

Perfect Consonant

Semitones

half-steps

Cents

700

100 per semitone

Frequency 1

261.63 Hz

Frequency 2

392.00 Hz

The Perfect Fifth is the most consonant interval after the octave. It appears in nearly every musical tradition worldwide and forms the basis of the circle of fifths.

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Summary

Pick any two notes and instantly see the interval name, semitone count, quality, and consonance rating.

How it works

Select the root note (pitch and octave) from the first row of dropdowns.
Select the target note (pitch and octave) from the second row of dropdowns.
Toggle direction between Ascending and Descending to control which way the interval is measured.
The interval name, semitones, cents, quality, and consonance badge update automatically.
Use the Swap button to reverse the two notes without retyping.

Use cases

Music students quickly checking interval names and qualities during theory study.
Composers verifying the consonance of note pairs before writing harmonies.
Guitarists finding the semitone distance between any two frets or strings.
Piano students identifying intervals across the keyboard by octave and pitch.
Songwriters checking whether a melodic leap is a third, a fifth, or a seventh.
Music teachers demonstrating interval taxonomy in the classroom.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu