Major Third Examples
The following intervals are all Major thirds because the two notes are a third apart and contain exactly four half steps.
Major Third Test
There are two things that must be true for an interval to be a major third:
- The notes must be a third apart.
- There must be exactly 4 half steps between the notes.
Review the Interval Intro lesson if this is unfamiliar to you.
Let’s go through this test on the first interval, D to F#.
Is the Interval a Third?
Remember that the numeric portion of an interval can be thought of as the number of letter names between the notes, or the number of lines and spaces. Counting the numeric portion of an interval is inclusive of the written notes because we want to count each letter name/line/space, including those of the written notes.
If we start on D and count each line/space or letter name until we get to F#, we find that there are three letter names (D, E and F#). Therefore, the numeric portion of this interval is a third.
Notice that both the minor and major thirds are a third, even though there is an F natural in a minor third and an F# in a major third. This is why we need quality as well!
Is the Interval Major?
The quality of this interval is minor because it contains 3 half steps between the notes. Remember that a half step is the distance between the notes, so we count our starting note as zero (i.e., we do not count the first note because we have not traveled anywhere at that point).
Notice in the figure below that there are 4 chromatic notes from D to F. When we move from D to D# we have traveled our first half step, so we count that as 1. In total, there are 3 half steps between D and F, which makes this interval a minor third.
Yes, the Counting is Confusing (at first!)
To help keep it straight when you start on 1 vs start on 0:
- Numeric – we want to count all letter names or lines/spaces, so we start on 1 to include the first written note.
- Quality – we want the distance between the notes, so we start on 0 because we have not gone anywhere on the first note.
Practice
Perform the major third test yourself on the remaining intervals in the Major Third Examples section.