Interval Music Theory Calculator

Understanding musical intervals is fundamental to music theory. This calculator helps you determine the distance between two notes in semitones and cents, visualize the interval on a piano, and understand its classification.

What is an interval in music theory?

An interval in music theory is the distance between two pitches. It's measured in semitones (half-steps) and can be classified by quality (major, minor, perfect, etc.) and size (unison, second, third, etc.).

For example, the interval between C and D is a minor second (1 semitone), while C and E is a major second (2 semitones).

In equal temperament tuning, each semitone is approximately 100 cents, where a whole tone is 200 cents.

How to calculate musical intervals

To calculate the interval between two notes:

Identify the pitch class (letter name) of each note
Count the number of semitones between them
Determine the interval quality based on the semitone count
Classify the interval by size (unison, second, third, etc.)

Interval in semitones = (Note 2 position - Note 1 position) mod 12

For example, the interval between C (position 0) and E (position 4) is 4 semitones, which is a major third.

Types of musical intervals

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

Semitones	Interval Name	Example
0	Perfect Unison	C to C
1	Minor Second	C to C#
2	Major Second	C to D
3	Minor Third	C to D#
4	Major Third	C to E
5	Perfect Fourth	C to F
6	Tritone	C to F#
7	Perfect Fifth	C to G
8	Minor Sixth	C to G#
9	Major Sixth	C to A
10	Minor Seventh	C to Bb
11	Major Seventh	C to B

Practical applications of interval calculation

Understanding musical intervals has practical applications in:

Composing music by creating harmonious relationships between notes
Improvising by knowing which intervals sound good together
Transposing music between keys
Analyzing existing music to understand its structure
Learning to play instruments by understanding the distances between notes

In jazz music, intervals are particularly important for creating blues and chromatic progressions.

Frequently Asked Questions

What is the difference between a major and minor interval?

A major interval has a larger semitone distance than its minor counterpart. For example, a major second is 2 semitones, while a minor second is 1 semitone.

How do I calculate the interval between two notes on a piano?

Count the number of keys between the two notes. Each white key represents one semitone, and each black key represents one semitone as well.

What is the largest interval in music theory?

The largest interval is the octave, which spans 12 semitones. It's considered the most stable and consonant interval.

How do I use this calculator to find intervals in my music?

Simply select the two notes you want to compare, click "Calculate," and the calculator will show you the interval in semitones, cents, and its classification.