Music Scale & Chord Generator

What a scale really is: a pattern of intervals

A musical scale is not a fixed set of notes — it's a pattern of steps that you can start on any note. Western music divides the octave into twelve equal semitones (the twelve keys, white and black, before the pattern repeats). A scale is simply a recipe of how many semitones to jump between successive notes. This tool stores each scale as a list of semitone offsets from the root. The Major scale, for instance, is 0, 2, 4, 5, 7, 9, 11 — meaning whole-whole-half-whole-whole-whole-half (W–W–H–W–W–W–H). Apply that same recipe starting on C and you get C, D, E, F, G, A, B; start it on G and you get G, A, B, C, D, E, F♯. Same pattern, different key.

A worked example: building C Major and A Minor

Pick root C and scale Major. The tool walks the offsets from C (index 0 of the twelve notes): 0→C, 2→D, 4→E, 5→F, 7→G, 9→A, 11→B. Those seven notes light up on the SVG piano so you can see the shape — all white keys, in this case. Now switch the root to A and the scale to Natural Minor (offsets 0, 2, 3, 5, 7, 8, 10): A, B, C, D, E, F, G — again all white keys. That's no coincidence: C Major and A Minor contain exactly the same notes, which is why A Minor is called the relative minor of C Major. Seeing both highlighted on the keyboard makes that relationship obvious in a way a list of letters never does.

The twelve scales on offer, and how they differ

The three minor scales are worth distinguishing. Natural Minor is the plain dark scale. Harmonic Minor raises the seventh note by a semitone (offset 11 instead of 10), creating the strong leading-tone pull that makes minor-key cadences feel finished — at the cost of an exotic gap between the 6th and 7th. Melodic Minor raises both the 6th and 7th, smoothing that gap, which is why it's traditionally used ascending in melodies.

Diatonic chords: the chords that "belong" to a key

Below the keyboard the tool builds the diatonic triads — the chords you get by stacking thirds on each scale degree using only notes from the scale. For a seven-note scale this yields seven chords, labelled with Roman numerals. In a Major key the qualities are always I, ii, iii, IV, V, vi, vii°: uppercase for major triads, lowercase for minor, and the small circle marking the diminished chord on the seventh degree. So in C Major you get C, Dm, Em, F, G, Am, Bdim. This is the practical heart of songwriting — the overwhelming majority of pop and folk progressions are just sequences of these chords (the famous I–V–vi–IV, for example, is C–G–Am–F in C Major). The tool computes each triad's quality from the actual semitone gaps between its root, third and fifth, so the labels stay correct across every scale, not just Major.

Hearing it: how Play Scale works

The Play Scale button uses the browser's Web Audio API — no plugin, no download. It synthesises each note as a triangle-wave tone and plays them in sequence, about a third of a second apart, with the pitch of each note calculated from the equal-temperament formula (every semitone multiplies the frequency by the twelfth root of two, anchored to A4 = 440 Hz). Because it's generated on the fly in your browser, playback is instant and works offline. As the scale climbs past the top of the octave the tool steps up to the next octave so the line keeps rising naturally rather than wrapping around.

How to actually use this

• Learn a song's key. If a song is in G Major, generate that scale, and you'll see the notes and the seven chords you can likely build a part from.
• Find safe notes to improvise. For a quick solo over a minor groove, the minor pentatonic or blues scale gives you five or six notes that rarely sound wrong.
• Hear the modes. Generate Dorian and then Phrygian on the same root and press Play on each — the difference between a single altered note is far easier to hear than to read.
• Practise scale shapes. Use the highlighted piano keys as a visual fingering guide while you play along on a real instrument.