Fifth / Perfect Fifth

What are fifths in music? We’ll explain! 

Fifth as a note on a musical scale and the perfect fifth interval 

The fifth in music means the fifth note of a musical scale. It doesn’t automatically mean that the first and fifth notes of each scale create the perfect fifth interval. Those are two different things. The fifth note is an important part of many chords. For instance, guitar power chords are based on Root and Fifth.

Fifth or Perfect Fifth

Fifth or Perfect Fifth

Fifth as an interval

The fifth or “perfect fifth” is the musical interval between two notes/pitches located at a distance of three tones and one halftone from each other. What are tones and halftones you ask? Let us show you:

Fifth as interval

Fifth as interval

Simply put, a tone is the distance between two neighboring keys on the piano keyboard, separated by one black key. 

A halftone is the distance between two neighboring notes, which don’t have a black key in between. 

How to find the perfect fifth? 

Let’s find a Fifth interval from C. The main thing we will be guided by is the distance of 3,5 tones. Let’s stick with the piano keyboard, for it shows all notes in a logical way. 

Perfect Fifth example

Perfect Fifth example

Let’s go up from C to D, crossing on black key and getting one tone. Then from D to E notice there is another black key so we’re another tone up. That’s two tones in total so far. Remember that we need three and a half tones! Let’s go further: E to F there is no black key. This means we’re up a halftone. So, two and a half tones up until now. We need one more tone. F to G has black key in between. We made it! We’ve just found the perfect fifth interval from C. Moving three and a half tones from C takes us to G. Playing C and G at the same time, we hear the perfect fifth interval.

How to find the fifth in different keys?

The keys may be different, but the way to find your fifth from any desired note is the same, as we described above: you have to count tones to get the right distance between notes, which will create the perfect fifth interval.

Here is the list of perfect fifth intervals in the C major scale and universal roman numerals. Now you can number any major scale and find all perfect fifths there.

Perfect fifths in C major scale

Perfect fifths in any major keys

C – G;

D – A;

E – B;

F – C;

G – D;

A – E.

I – V;

II – VI;

III – VII;

IV – I;

V – II;

VI – III.

How to find the fifth in a minor scale? 

Since we have three types of minor natural minor, harmonic minor and the melodic minor it’s impossible to make a universal formula for all of them. But don’t worry! The most important thing is that now you can find your perfect fifth interval from any desired note, since you know that this interval is three and a half tones. So, you need just to count tones. 

How to find the Perfect fifth extra example

With this knowledge you can find the perfect fifth interval in any major or minor keys. Just be careful, when you start counting from your initial note, the notes you come to next may not belong to the scale you’re in. 

For instance, we’re in C major scale. And we want to find the perfect fifth from the note B. Let’s start counting: from B to C = 0,5 tone; C to D = 1 tone; D to E = 1 tone. We need 1 tone to reach the 3,5, but E to F = 0,5 tone. Therefore, we’re landing on F#, because E to F# = 1 tone. So, the perfect fifth from B will be B-F#. As you can see, F# is not in C major scale. The same principle works for minor scales. 

More to read about Fifth or Perfect fifth:

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