π Interval Calculator
Identify the interval between any two musical notes.
How to Use This Calculator
Select the two notes you want to compare. Each note has a dropdown for the note name and a separate dropdown for the octave number. The calculator works upward or downward: if Note 1 is above Note 2, the direction shows as descending. The interval grid at the bottom shows all 13 intervals from C for quick reference.
Select Note 1 from the first dropdown (C, C#, D, and so on) and its octave from the second. Start with the lower note here if you want an ascending interval.
Select Note 2 and its octave. The calculator measures the distance from Note 1 to Note 2 and identifies the interval, including compound intervals larger than an octave.
Read the interval name (Perfect 5th, Minor 3rd, Tritone, etc.) and the semitone count. The frequency ratio shows you the acoustic relationship between the two pitches in equal temperament.
Check the consonance rating below the result. Perfect and imperfect consonances (5ths, 3rds, 6ths) blend smoothly. Dissonant intervals (2nds, 7ths, tritone) create tension that typically resolves.
Interval Semitone Reference
Every interval has a fixed number of semitones. A perfect 5th is always 7 semitones, regardless of which notes you use: C to G, D to A, F# to C# β all 7 semitones, all perfect 5ths. The quality name (perfect, major, minor, augmented, diminished) classifies the interval by how it sounds and how it functions harmonically. Perfect intervals are the most stable; major and minor intervals are moderately stable; diminished and augmented intervals are the most unstable and tend to resolve.
Real-World Examples
When You Need This
When you're composing a melody or harmonizing vocals, knowing the interval between two notes tells you whether they will blend or clash. A major 6th between a lead vocal and a harmony part sounds full and open. A minor 7th stacks nicely in jazz but creates obvious tension in a pop ballad. Before you commit to a harmonic choice in an arrangement, check the interval here to understand what you're working with theoretically, then trust your ears to confirm.
Ear training practice is one of the best uses of this tool. Pick an interval from the reference grid, find an example in a song you know well (a perfect 4th ascending sounds like the opening of "Here Comes the Bride," a minor 3rd descending sounds like the opening of "Hey Jude"), and train your ears to recognize the distance. Checking the semitone count here while you practice keeps you grounded in the theory behind what your ears are learning.
Frequently Asked Questions
What is a musical interval?
An interval is the distance between two pitches. It's named by both its quality (perfect, major, minor, augmented, diminished) and its numeric value (unison, 2nd, 3rd, 4th, 5th, 6th, 7th, octave).
What is the difference between major and minor intervals?
Major intervals are one semitone wider than minor intervals. A major 3rd = 4 semitones (C to E). A minor 3rd = 3 semitones (C to Eb). Perfect intervals (4th, 5th, octave) have no major/minor β just perfect.
What is a tritone?
The tritone (augmented 4th / diminished 5th) is exactly 6 semitones β halfway through the octave. It was historically called "diabolus in musica" (the devil in music) for its dissonant sound.
What are consonant vs dissonant intervals?
Consonant: perfect unison, octave, 5th, 4th, major/minor 3rd, major/minor 6th. Dissonant: major/minor 2nd, major/minor 7th, tritone. These are perceptual categories that vary across musical cultures.
What is the frequency ratio of an interval?
In equal temperament: ratio = 2^(semitones/12). A perfect 5th (7 semitones) = 2^(7/12) β 1.498. The "perfect" ratios in just intonation are 3/2 for a 5th and 2/1 for an octave.