Reference
How the Free Scale Finder works
This page documents the note rules, the three matching modes, the supported chord syntax, the scale catalogue and the limits of the instrument views. It is written so you can check what the tool is actually doing.
The short version
- Enter notes. Paste them with spaces, commas or new lines. Octaves are optional and are ignored for matching.
- Optionally choose a tonic. Unknown is the default. The first note is never treated as the tonic.
- Compare match modes. Exact uses the same pitch classes. Contains allows extra scale notes. Nearby allows one note of difference in each direction.
- Select a result. The detail panel shows the tonic, spelled notes, degrees, intervals and supporting chords.
- See and hear it. The piano and guitar are synchronized with the same notes. Playback is synthesized locally after a button press.
Note input rules
Notes are parsed as pitch classes. A, A♯ and B♭ are different spellings, but A♯ and B♭ compare as the same pitch class. The input accepts:
- Letters A through G in upper or lower case.
- Sharps and flats as
#or♯, andbor♭. - Double sharps and double flats such as F## or Bbb.
- Optional octave numbers such as C4, Eb3 or A-1. The octave is displayed only as part of the token; it does not affect matching.
Duplicate pitch classes are removed, and the input summary tells you how many were removed. Invalid tokens are never silently dropped: they produce a visible error while the valid notes continue to be used. For example, C H E reports “H” as invalid and keeps C and E.
Matching modes and ordering
Matching is deterministic. For a given note set and tonic filter, the same results appear in the same order. The tool does not use a model, a probability or a confidence percentage.
Exact note set
A scale is an exact match when its pitch-class set has the same size as your input and contains every input pitch class. Enharmonic spellings do not create extra matches.
Contains my notes
A scale is a containing match when every input pitch class is in the scale. It may have extra notes. Exact matches are included here and labelled “Exact set”, so you can see both the strict and broad answers in one place.
Nearby matches
Nearby is an explicit one-pitch-class tolerance: at most one input note is outside the scale, and at most one scale note is missing from your input. This covers one added note, one removed note or one substitution. Exact matches are not repeated in the nearby list. Every nearby card names the input notes outside the scale and the scale notes missing from your input.
How results are ordered
Exact results are ordered by an editorial commonness rank, then by tonic pitch class. Containing results put exact matches first, then favour the smallest number of extra notes, then commonness. Nearby results favour the smallest total difference, then commonness. This is a reading aid, not a score.
What the tonic filter does
The tonic is the tonal centre you choose to treat as “home”. It is optional. With Unknown selected, every tonic is considered, so the same seven notes can produce C major, D Dorian, E Phrygian, F Lydian, G Mixolydian, A natural minor and B Locrian. Those are distinct modes with different tonics, not aliases, and the tool does not collapse them.
Choosing a tonic filters the candidates to that tonal centre. The notes themselves remain the same; the filter changes which interpretation is shown. The tool never assumes that the first note you type is the tonic.
Chord input and supported syntax
Chord input is a shortcut for adding notes, not a separate chord finder. The parser is strict: a quality is accepted only if it is on the supported list, and unsupported input is rejected with a visible message rather than guessed.
Supported qualities:
- Triads: major (
C), minor (Cm), diminished (CdimorC°), augmented (CaugorC+). - Suspended:
Csus2,Csus4. - Sevenths:
Cmaj7orCΔ7,C7,Cm7,Cdim7orC°7,Cm7b5orCø7,Caug7,C7sus4,CmMaj7. - Slash bass: one bass note, such as
C/GorAm7/C.
Extensions such as add9, 9, 11 and 13, altered dominants, multiple slashes and free-form text are not supported. Chord qualities are case-sensitive where the symbol requires it: Cm is minor and CM is major.
The chord parser expands the chord to its pitch classes and puts those notes into the note input. The chord root does not automatically become the tonic. If the bass note is already a chord tone, it does not add a new pitch class to the matching set.
Spelling and intervals
Matching uses pitch classes, but results use spelled notes. For seven-note scales, pentatonic scales, blues scales and the diminished scales, spelling is letter-aware: each scale degree uses the next letter name, and accidentals are calculated from the target pitch. This is why F♯ major contains E♯ rather than F, and why C harmonic minor contains B rather than C♭.
Whole-tone and chromatic scales use readable enharmonic tables, because they do not have a single conventional letter-based spelling in every key. The tool chooses the spelling with the lower accidental cost. It never invents a pitch class; the interval list and the note list always agree.
Intervals are shown as semitone offsets from the tonic, beginning with 0. Degree labels use 1, ♭3, ♯4 and similar notation. For bebop scales, the added chromatic note is labelled “passing”.
The reviewed scale catalogue
The catalogue contains 21 scale definitions across 12 roots. Each root is spelled with the lowest-cost common spelling, so some enharmonic roots appear in their more readable form. The table shows the interval formula and the C-root spelling for reference.
Major & minor
| Scale | Intervals | Notes from C | What it is |
|---|---|---|---|
| Major (Ionian) | 0 – 2 – 4 – 5 – 7 – 9 – 11 | C D E F G A B | The familiar seven-note major scale. Its modes share the same notes but have different tonal centres. |
| Natural minor (Aeolian) | 0 – 2 – 3 – 5 – 7 – 8 – 10 | C D E♭ F G A♭ B♭ | The relative minor scale. It shares its notes with a major scale a minor third above. |
| Harmonic minor | 0 – 2 – 3 – 5 – 7 – 8 – 11 | C D E♭ F G A♭ B | Natural minor with a raised seventh, producing a strong dominant chord and an augmented third-degree triad. |
| Melodic minor (ascending) (Jazz minor) | 0 – 2 – 3 – 5 – 7 – 9 – 11 | C D E♭ F G A B | The ascending melodic minor form. It has a raised sixth and seventh compared with natural minor. |
Modes
| Scale | Intervals | Notes from C | What it is |
|---|---|---|---|
| Dorian | 0 – 2 – 3 – 5 – 7 – 9 – 10 | C D E♭ F G A B♭ | A minor-flavoured mode with a natural sixth, common in jazz, folk and modal rock. |
| Phrygian | 0 – 1 – 3 – 5 – 7 – 8 – 10 | C D♭ E♭ F G A♭ B♭ | A minor mode with a flat second, giving a distinctive Spanish or metal flavour. |
| Lydian | 0 – 2 – 4 – 6 – 7 – 9 – 11 | C D E F♯ G A B | A major mode with a raised fourth, often heard as bright or floating. |
| Mixolydian | 0 – 2 – 4 – 5 – 7 – 9 – 10 | C D E F G A B♭ | A major mode with a flat seventh, common in rock, blues and dominant-tonic harmony. |
| Locrian | 0 – 1 – 3 – 5 – 6 – 8 – 10 | C D♭ E♭ F G♭ A♭ B♭ | The seventh mode of the major scale, with a flat second and flat fifth. |
Pentatonic & blues
| Scale | Intervals | Notes from C | What it is |
|---|---|---|---|
| Major pentatonic | 0 – 2 – 4 – 7 – 9 | C D E G A | Five notes from the major scale. It does not define a full seven-degree chord set. |
| Minor pentatonic | 0 – 3 – 5 – 7 – 10 | C E♭ F G B♭ | Five notes from natural minor. It is common in rock, blues and pop solos. |
| Major blues | 0 – 2 – 3 – 4 – 7 – 9 | C D E♭ E G A | A major pentatonic with an added flat third. It is a melodic colour, not a seven-degree chord scale. |
| Minor blues | 0 – 3 – 5 – 6 – 7 – 10 | C E♭ F G♭ G B♭ | A minor pentatonic with an added flat fifth. It is a melodic colour, not a seven-degree chord scale. |
Symmetric
| Scale | Intervals | Notes from C | What it is |
|---|---|---|---|
| Whole tone | 0 – 2 – 4 – 6 – 8 – 10 | C D E F♯ G♯ A♯ | Six evenly spaced notes. It has no standard seven-degree chord set. |
| Chromatic | 0 – 1 – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9 – 10 – 11 | C C♯ D D♯ E F F♯ G G♯ A A♯ B | All twelve pitch classes. Every note collection is contained in it, so it is rarely a useful identification on its own. |
| Whole-half diminished (Diminished (whole-half)) | 0 – 2 – 3 – 5 – 6 – 8 – 9 – 11 | C D E♭ F G♭ A♭ A B | An eight-note symmetric scale alternating whole and half steps. It does not use a seven-degree chord set. |
| Half-whole diminished (Dominant diminished) | 0 – 1 – 3 – 4 – 6 – 7 – 9 – 10 | C D♭ E♭ E F♯ G A B♭ | An eight-note symmetric scale alternating half and whole steps. It does not use a seven-degree chord set. |
Bebop
| Scale | Intervals | Notes from C | What it is |
|---|---|---|---|
| Bebop major | 0 – 2 – 4 – 5 – 7 – 8 – 9 – 11 | C D E F G G♯ A B | A major scale with a chromatic passing tone between the fifth and sixth degrees. |
| Bebop dominant | 0 – 2 – 4 – 5 – 7 – 9 – 10 – 11 | C D E F G A B♭ B | A mixolydian scale with a chromatic passing tone between the flat seventh and the root. |
Other
| Scale | Intervals | Notes from C | What it is |
|---|---|---|---|
| Harmonic major | 0 – 2 – 4 – 5 – 7 – 8 – 11 | C D E F G A♭ B | A major scale with a flat sixth, combining a major third with a minor sixth. |
| Hungarian minor | 0 – 2 – 3 – 6 – 7 – 8 – 11 | C D E♭ F♯ G A♭ B | A harmonic minor scale with a raised fourth, often described as an Eastern European or gypsy-minor colour. |
Supporting chords
The chord cards under a selected scale are supporting information, not a second chord finder. Seven-note scales are harmonised by stacking scale degrees 1–3–5. Major, natural minor, harmonic minor, melodic minor, harmonic major, Hungarian minor and the modes therefore produce their own diatonic triads.
Bebop major and bebop dominant show the chords of their parent major or Mixolydian scale, with a note explaining the added passing tone. Pentatonic, blues, whole-tone, chromatic and diminished scales do not have a seven-degree chord set forced onto them; the panel explains why instead. This avoids inventing harmony that the scale does not define.
Piano, guitar and playback
The piano shows one octave, C4–B4. The guitar uses standard tuning E2–A2–D3–G3–B3–E4 and frets 0–12. Both views share the same input notes and selected scale, and both can add or remove pitch classes by clicking or keyboard activation.
Scale tones are labelled with degrees and the tonic is labelled “R”, so the display does not rely on colour alone. The guitar is a scale-tone map: highlighted cells do not represent a playable chord shape, fingering or voicing. The left-handed option mirrors the fret order while keeping the string labels visible.
Playback uses the Web Audio API with synthesized triangle oscillators. Nothing is downloaded as a sample, nothing autoplays, and audio starts only after you press a play button. A new playback stops the previous one. The ascending and descending buttons play the scale from the tonic; the tonic button plays the tonic alone.
Copying, sharing and saved state
Copy notes and copy results produce plain text. Share links encode the notes, tonic, matching mode, selected scale, instrument and left-handed preference in the URL fragment, after the #. Fragments are not sent to the server and are not separate crawlable pages. Invalid or malformed shared state is rejected instead of being applied.
The optional “restore last session” feature uses local storage in your browser. It is not an account and it does not sync between devices. The privacy page lists exactly what is stored.
Limitations
- The tool matches pitch classes, not musical function, melody, rhythm, voicing or chord progression.
- A scale result is a possible interpretation. The same notes can belong to several modes and tonal centres.
- The catalogue is finite. A scale outside the catalogue will not appear, although the chromatic scale will technically contain any input set.
- Chord input supports the listed qualities only. It is not a general chord chart or tablature parser.
- Playback is a reference tone, not a produced recording. Audio support depends on the browser and its sound permissions.
- The guitar view is a scale-tone map, not a fingering engine. It does not suggest which notes to play together.
If a scale spelling or chord result looks wrong, use the contact page and include the exact input, the result you expected and the result you saw.
Questions
Common scale finder questions
The dedicated FAQ covers note matching, chord syntax, tonic settings, nearby results, instrument views and privacy in plain language.