Intervals on the Fretboard
In standard tuning, an interval's shape never changes — learn it once on any string and you can play it anywhere on the neck.
Why shapes repeat
The distance between adjacent strings in standard tuning is fixed — a perfect 4th almost everywhere, and a major 3rd between the G and B strings. Because that distance never changes, a two-note interval keeps the exact same finger shape as you slide it up or down the neck, or move it to a different pair of strings (as long as that pair isn't the G-B pair).
The building blocks: half steps and whole steps
Every named interval is really just a fixed number of semitones (half steps). A minor 3rd is 3 semitones, a major 3rd is 4, a perfect 5th is 7, and so on. Once you can count frets, you already know how to measure any interval — the interval names are just convenient labels for specific fret distances.
Common shapes you'll use constantly
An octave is the same string 12 frets up, or two strings over and two frets down. A perfect 5th is two frets up and one string over. A major 3rd and minor 3rd are the shapes behind every major and minor chord you build. The one thing to watch for: any shape that crosses the G-to-B string pair needs one extra fret to keep the same interval, because that pair is tuned a major 3rd apart instead of a perfect 4th.
Common questions
What is a movable shape?
A fingering pattern for an interval, chord, or scale that keeps the exact same shape and sound as you slide it to a new fret or a new starting string.
Why do shapes change near the G and B strings?
Standard tuning is a major 3rd between the G and B strings, while every other adjacent pair is a perfect 4th. Shapes that cross this pair need one extra fret to preserve the same interval.
What is the fastest interval to learn first?
The octave and the perfect 5th — both show up constantly in power chords, bass lines, and chord voicings, and both have simple, easy-to-remember shapes.
Do interval shapes work in any key?
Yes. Because a shape is defined by fret and string distance rather than by specific note names, the same shape produces the same interval starting from any root, in any key.
Hear any interval instantly
Melody Monkey plays and labels intervals live as you explore scales and chords.
Open the ear trainer →Still stuck? Ask Your Personal Music Teacher about Intervals on the Fretboard →