An interval is the measure of distance between two notes in music.
To count an interval, lets use an example. Say we want to know the interval of D to G, ascending. So we start on D = 1, and count up. D1, E2, F3, G4. There! We count to four, and so we know we have some type of fourth. Always count the letters this way to determine the type of interval, for example, whether it’s a fourth of a fifth. Some intervals are exactly equivalent but have different names, and that is how you make the distinction.
We have types of intervals. We’ll use the D major scale (our most familiar scale) to calculate some intervals.
| Bottom note | Top note | Interval |
| D | D (same note) | Perfect Unison (same pitch) |
| D | E♭ | Minor Second |
| D | E | Major Second |
| D | F | Minor Third |
| D | F# | Major Third |
| D | G | Perfect Fourth |
| D | G# | Augmented Fourth (Tritone) |
| D | A♭ | Diminished Fifth (Tritone) |
| D | A | Perfect Fifth |
| D | B♭ | Minor Sixth |
| D | B | Major Sixth |
| D | C | Minor Seventh |
| D | C# | Major Seventh |
| D | D (high) | Perfect Octave |
Notice we classify the intervals by their type: perfect, major, minor, augmented, or diminished.
| Classification | Intervals that it can apply to |
| Perfect | Unisons, fourths, fifths, and octaves |
| Major/Minor | Seconds, thirds, sixths, sevenths |
| Diminished/Augmented | ALL |
We won’t talk here about how the classifications of diminished and augmented can apply to the major/minor intervals. They are mostly important for the perfect intervals, since perfect intervals can’t be major or minor.
The perfect intervals have a sort of neutral quality, meaning, they don’t sound happy or sad. We tune our violins by fifths (the interval distance between any two adjacent strings). It is easy to tune this way because these intervals are extremely obvious if they are out of tune. They tend to clash more noticeably if they’re even slightly off. This effect is also noticed when we attempt to play octaves. They’re quite unforgiving!
The perfect intervals can be made bigger or smaller, but we use the terms diminished (smaller) and augmented (bigger) to categorize these. That is why a perfect fourth is from D to G and an augmented fourth is from D to G#—we made the fourth bigger by one half step. But, if we went up to A♭ instead (the same note as G#!) we would now have a diminished fifth because we’re going from D to A, not D to G. So, an augmented fourth = a diminished fifth, and there is a more general term applied to this very dissonant (clashing) interval: a tritone.
For violinists, the easiest way to remember the intervals is by feeling them on our actual fingerboards. Because our strings are tuned consistently in fifths (the distance between adjacent strings is always the same) we can consistently calculate intervals this way. The violin becomes a sort of interval calculator!
| Interval | Violin-Based Calculation |
| Perfect Unison | The same note. Ex: playing 4th finger D on the G string and open D at the same time. |
| Minor Second | A half step! We’ve been talking about these forever! |
| Major Second | A whole step! Whole step = two half steps |
| Minor Third | Think of this one as a whole step PLUS a half step. It usually spans three fingers. Like going from 0 to 2, 1 to 3, 2 to 4. |
| Major Third | Think of this one as two whole steps added together. Just like a minor third, it will usually span three fingers. |
| Perfect Fourth | This one is two whole steps plus a half step. But, usually, you can think of it as a whole step down and then up a string. So, if you have F#, and you want a perfect fourth above it, go down a whole step (E) and up a string from there (B) and that’s the note! |
| Tritone | This is a half step bigger than a perfect fourth and a half step smaller than a perfect fifth. Like the perfect fourth, you can imagine this one easily on the violin: go down a half step and up a string and that’s your note. Ex: To get a tritone above E, go down a half step (E♭ or D#) and up a string (B♭ or A#). |
| Perfect Fifth | Directly up a string! D to A, A to E, E to B. Try it! This is the easiest one! Just go directly up to the next string with whatever finger (or open string) you’re already using. |
| Minor Sixth | Directly up a string plus a half step. This will feel like a half step between your two fingers, just they’re on two different strings. |
| Major Sixth | Directly up a string plus a whole step. This will feel like a whole step between your two fingers, just they’re on two different strings. |
| Minor Seventh | A whole step beneath the octave. So, if you start on open D and need a minor seventh above, go up to 3rd finger D (the octave) and then down a whole step to C. You can also think of this one as adding a half step to a major sixth. Both work! |
| Major Seventh | A half step beneath the octave. Like the minor seventh but with a half step. |
| Perfect Octave | The next highest pitch with the same name. D to high D, 1st finger E to open E, etc. |
A more concise table is as follows:
| Interval | Violin-Based Calculation |
| Perfect Unison | The same note |
| Minor Second | A half step |
| Major Second | A whole step |
| Minor Third | A whole step plus a half step |
| Major Third | Two whole steps added |
| Perfect Fourth | A whole step down then up a string |
| Tritone | Down a half step and up a string |
| Perfect Fifth | Directly up a string |
| Minor Sixth | Directly up a string plus a half step |
| Major Sixth | Directly up a string plus a whole step |
| Minor Seventh | A whole step beneath the octave |
| Major Seventh | A half step beneath the octave |
| Perfect Octave | The next highest pitch with the same name |