Intervals on Your Instrument
Twelve distances, each with a number, a name and a sound — the same from every note.
An interval is the distance between two notes, counted in semitones — one fret, one key, the black ones included. There are twelve inside an octave, and each has a number, a name and a sound of its own; on your instrument each one is the same distance from every note, which is what makes it learnable. Above, every root and every fifth on the guitar. Tap a note to hear it, the picker under the figure changes the instrument, and the figure follows the text from here — once you have tapped anything on the page, each interval below plays as you reach it.
The twelve
One or two semitones is a step; anything wider is a leap. Most melodies move in steps and leap to chord tones — Songwriting basics has that side of it. Here are the twelve, by size, each boxed on the figure and sounded as you scroll to it, and each with the place you will meet it.
| Semitones | Degree | Name |
|---|---|---|
| 0 | 1 | unison |
| 1 | ♭2 | minor second |
| 2 | 2 | major second |
| 3 | ♭3 | minor third |
| 4 | 3 | major third |
| 5 | 4 | perfect fourth |
| 6 | ♯4 | tritone |
| 7 | 5 | perfect fifth |
| 8 | ♭6 | minor sixth |
| 9 | 6 | major sixth |
| 10 | ♭7 | minor seventh |
| 11 | 7 | major seventh |
| 12 | 8 | octave |
The minor second
One semitone ♪ — the half step, and the roughest pair there is. It is the pull under everything: the 7 rising to the octave is this distance, and so is phrygian's dark ♭2 leaning back onto the root.
The major second
Two semitones ♪ — the whole step, five of the major scale's seven steps. Rough held together, but the ordinary move in a melodic line: most of a tune is made of these.
The minor third
Three semitones ♪ — the minor triad's third, the minor pentatonic's opening leap from the root, and the first note the blues bends. Sweet, and a shade darker than the major third.
The major third
Four semitones ♪ — the major triad's third. Major or minor is this one semitone, and nothing else: the third is what a chord's mood is made of. It is the fifth harmonic, the first note the harmonic series adds that is not a root or a fifth.
The perfect fourth
Five semitones ♪ — open and a little hollow. The next string up on a guitar or bass; the IV chord; a suspended chord's 4 leaning down onto the 3. The fifth turned over: G up to C is a fourth, C up to G a fifth.
The tritone
Six semitones ♪ — exactly half the octave, and the one interval that turns over into itself. It is the engine of the dominant seventh chord, its 3 against its ♭7, which is why a V7 wants to go home; on its own it is lydian's ♯4 and the blues' ♭5.
The perfect fifth
Seven semitones ♪ — the smoothest thing after the octave. The power chord, root & fifth, the V chord, the frame every triad hangs its third in, and the step of the circle of fifths. If a root has one companion, it is this one.
The minor sixth
Eight semitones ♪ — the minor scale's ♭6, and what makes it darker than dorian, which has the 6. The major third turned over, and the tenser for it.
The major sixth
Nine semitones ♪ — where the relative minor lives: C up to A. The major pentatonic's top note, the minor third turned over, and as sweet.
The minor seventh
Ten semitones ♪ — the note that makes a dominant seventh chord, mixolydian's ♭7, the blues' seventh. Rough enough to want to move, which is exactly what a V7 is for.
The major seventh
Eleven semitones ♪ — maj7's color, and the leading tone: a half step under the octave, pulling up into it. Together with the root it is nearly as rough as the ♭2, which is the same two notes the other way round.
The octave
Twelve semitones ♪ — the same note again, the twelfth fret of any string, the next C along the keyboard. It sounds so nearly like one note that it shares the name, and every C on the instrument is a place the pattern starts over; The notes has all of them.
Smooth and rough
The same twelve from the smoothest pair to the roughest: the octave ♪, 5 ♪, 4 ♪, 6 ♪, 3 ♪, ♭3 ♪, ♯4 ♪, ♭6 ♪, 2 ♪, 7 ♪, ♭7 ♪, ♭2 ♪. The smooth end is the chord tones — the 5, the two thirds, the 6 the relative minor sits on; the rough end is the semitones and their neighbors, where the pull is. Why that order is the order it is — the harmonic series, every ratio played. And each interval and the one that adds up to twelve are the same two notes the other way up (♭2 and 7, 2 and ♭7, ♭3 and 6, 3 and ♭6, 4 and 5; the tritone alone), which is why the list pairs off.
The same from every root
Here is the fifth across the whole instrument: every root and every 5, and the 5 at the same distance from every 1. Move the root to G and the picture moves; the numbers don't. The third is another distance, and it holds from every root too. On a neck that distance is a shape — the same two frets and strings wherever you put your hand. On a keyboard it is a count, and the pattern of black and white keys under the count changes with the key. On both it sounds the same, and that sameness is what the number names.
From here the lower note is the root, and an interval counted from the root is a scale degree — the number the figure labels a note with. A degree has no direction: the G below a C is still the 5, because you hear it against C, not against where you came from. That is why the whole instrument reads 1 and 5 and nothing else, and it is the idea the rest of the site runs on. The walkthrough, Notes, intervals and scales, builds it a step at a time.
On the guitar
Two ways to any interval: along the string, counting frets, or across, as a shape. The fifth is the next string up, two frets higher; the fourth the next string, same fret; the third the next string, one fret back; the octave two strings over and two frets up. Every one of them shifts a fret when it crosses from the G string to the B — the same irregularity as on The notes, and the only one.
On the piano
Count keys, black ones included: seven for a fifth, four for a major third, three for a minor third. There is a white-key shortcut — a fifth from a white key is four white keys up, every time but B to F — and the exception is exactly where the tritone hides. The third is where major and minor show themselves: from C the major third is white E and the minor third black E♭; from D both are white. The count is the same; the picture isn't, which is why a pianist learns keys as patterns rather than intervals as shapes.
On the ukulele
G, C, E, A: C to E a major third, E to A a fourth — the same relations as the guitar's top three strings, so that part of the guitar's map carries over. The high G string puts a fifth below the C string on the string above it, so the figure's box runs across the strings more than along them.
On the bass
Fourths throughout, so every interval is one shape on every pair of strings: the fifth two frets up on the next string, the octave two strings over and two up, wherever you are on the neck. The bass is the instrument on which "an interval is a shape" is simply true.
On the mandolin
Tuned in fifths: the 5 is the next course at the same fret, the 4 the next course two frets down, and a third across the courses is a stretch, so mandolinists play thirds along the string. Fewer strings' worth of shape, more frets' worth of counting.
What NoSheet does instead
The app never names an interval. It labels every note by its degree from a root that is sounding and moves each round, so a fifth is never "seven semitones from wherever you were" but the 5: heard, then found. That is the difference from interval ear training, which names the distance between two passing notes on a keyboard — the ear that plays needs each note against home. Root & fifth is that game without the microphone: the first two degrees, every key, on the instrument you play; the walkthrough is the lesson behind it.
Questions
- What is an interval in music?
- The distance between two notes, counted in semitones — one fret on a guitar, one key on a piano including the black keys. There are twelve inside an octave, each with a name and a number: one semitone is a minor second, seven a perfect fifth, twelve an octave.
- How many semitones are in a perfect fifth, a major third and a minor third?
- Seven, four and three. On a guitar a fifth is the next string two frets up, a major third the next string one fret back; on a piano count the keys, black ones included.
- What is the difference between a major third and a minor third?
- One semitone: four semitones above the root is a major third, three is a minor third. It is the note that decides whether a chord is major or minor — the root and fifth are the same in both.
- What is a tritone?
- Six semitones, exactly half an octave — the augmented fourth or diminished fifth. It sits inside every dominant seventh chord, between its third and its seventh, and is the reason a V7 chord wants to resolve home.
- What is the difference between an interval and a scale degree?
- An interval is the distance between any two notes; a scale degree is that distance counted from the root, folded into one octave, with no direction — the G below a C is still the 5. Every degree is an interval; most intervals aren't degrees.
- Do I need to learn interval names to play by ear?
- Not the names. The ear that plays needs each note as a distance from the root that is sounding — the degree — not the distance between two passing notes. NoSheet never names an interval; it labels every note by its degree and moves the root each round.