Music Interval Calculator: Thirds, Fifths and More
This music interval calculator names the interval between two notes: choose them and you get the interval name, the number of semitones, the inversion and the ratio in just intonation and equal temperament.
Example: First note (lower): C · Second note (upper): E → Interval: major third. Source: Wikipedia – Interval (music) (interval names, just ratios, cents). Updated: .
How it is calculated
An interval is the distance between two notes: C to E is a major third, four semitones wide. To name it, count the steps first and then the semitones.
How to determine an interval
Count the letter names from bottom to top: C–D–E makes three, so it is a third. The semitones decide the quality. Unisons, fourths, fifths and octaves are “perfect”; seconds, thirds, sixths and sevenths are “major” or “minor”. One semitone more makes an interval augmented, one semitone less diminished.
Just and equal temperament
In just intonation every interval has a simple ratio, such as 5:4 for the major third (about 386 cents). Pianos and guitars use equal temperament, where it is exactly 400 cents. The table shows both values.
- Minor third 6:5, major third 5:4, fourth 4:3, fifth 3:2, octave 2:1.
- The tritone (six semitones) is an augmented fourth and a diminished fifth at once.
Frequently asked questions
How do you identify an interval?
Count the steps from the lower to the upper note, counting the first note, and find the semitones. Together they give the name, for example four semitones over three steps: a major third.
How many semitones is a perfect fifth?
A perfect fifth is seven semitones, for example C to G. A diminished fifth is six and an augmented fifth eight.
What is the difference between major and minor intervals?
Major intervals (second, third, sixth, seventh) are one semitone wider than minor ones. A major third has four semitones, a minor third three.
What is the inversion of an interval?
The lower note moves up an octave. A major third becomes a minor sixth this way; the two step numbers always add up to nine.
Sources and legal basis
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