Interval Classification Music Calculator

This interval classification music calculator helps musicians and music theory students identify and classify musical intervals based on their semitone count. Whether you're composing, transcribing, or studying music theory, understanding interval classification is essential for creating harmonious melodies and chords.

What is Interval Classification?

In music theory, an interval is the distance between two pitches. Interval classification refers to the process of identifying and categorizing these intervals based on their size and quality. The classification system typically uses numbers (indicating the number of scale degrees between the notes) and quality descriptors (perfect, major, minor, augmented, or diminished).

For example, a "perfect fifth" is an interval that spans five scale degrees (like C to G) and has a specific frequency ratio that defines its "perfect" quality.

The most common interval classifications are:

Perfect intervals: Unison (0 semitones), Fourth (5 semitones), Fifth (7 semitones), Octave (12 semitones)
Major intervals: Second (2 semitones), Third (4 semitones), Sixth (9 semitones), Seventh (11 semitones)
Minor intervals: Second (1 semitone), Third (3 semitones), Sixth (8 semitones), Seventh (10 semitones)
Augmented intervals: One semitone larger than the perfect or major version
Diminished intervals: One semitone smaller than the perfect or minor version

How to Use This Calculator

To classify a musical interval using this calculator:

Enter the starting note (e.g., C)
Enter the ending note (e.g., G)
Click "Calculate Interval"
The calculator will display the interval classification, semitone count, and quality

Formula used:

Interval = (Ending note position - Starting note position) mod 12

Quality is determined based on the interval's semitone count and standard musical theory conventions.

For example, if you enter C (position 0) and G (position 7), the calculator will identify this as a perfect fifth (7 semitones).

Interval Types

Musical intervals can be classified into several types based on their quality and size:

Interval Type	Semitones	Example
Perfect Unison	0	C to C
Minor Second	1	C to C#
Major Second	2	C to D
Minor Third	3	C to D#
Major Third	4	C to E
Perfect Fourth	5	C to F
Augmented Fourth / Diminished Fifth	6	C to F#
Perfect Fifth	7	C to G
Minor Sixth	8	C to A♭
Major Sixth	9	C to A
Minor Seventh	10	C to B♭
Major Seventh	11	C to B
Perfect Octave	12	C to C

This table shows the standard interval classifications and their corresponding semitone counts. The examples are based on the note C as the starting pitch.

Common Musical Intervals

Here are some of the most commonly used intervals in music:

Perfect Fifth (7 semitones): The foundation of Western harmony, used in chords and progressions.
Major Third (4 semitones): Creates a bright, consonant sound when combined with a perfect fifth.
Minor Third (3 semitones): Adds a darker, more tense quality to chords.
Perfect Fourth (5 semitones): Used in jazz and modern music for its unique color.
Major Sixth (9 semitones): Adds a bright, open quality to chords.
Minor Sixth (8 semitones): Creates a more tense, darker sound than the major sixth.

Remember that interval quality can change based on the key and context. For example, a major third in one key might be a minor sixth in another.

FAQ

What is the difference between a major and minor interval?

Major and minor intervals differ by one semitone. For example, a major second is two semitones (C to D), while a minor second is one semitone (C to C#). The quality of the interval affects its harmonic color and function in music.

How do I classify an augmented interval?

An augmented interval is one semitone larger than the perfect or major version of that interval. For example, an augmented fourth is six semitones (C to F#), which is one semitone larger than a perfect fourth (C to F).

What is the difference between a diminished fifth and an augmented fourth?

Both intervals are six semitones apart. The difference is in their naming convention. A diminished fifth is six semitones smaller than a perfect fifth (C to F#), while an augmented fourth is six semitones larger than a perfect fourth (C to F#).