Why does F major show B♭ instead of A♯?

Because they are the same key on a piano and different notes in music. A major scale uses each letter name once: F, G, A, then a kind of B, then C, D, E. Calling it A♯ would use A twice and skip B, which makes the key signature impossible to write and the sheet music harder to read.

What is the difference between a mode and a scale?

A mode is a scale — the word usually means one of the seven scales you get by starting the major scale's notes on each of its degrees. D Dorian, E Phrygian and A Aeolian all use the white notes, but each treats a different note as home, and that changes which intervals sit above the tonic and so how the scale sounds.

Should I practise scales from the circle of fifths instead of at random?

Both have a place. Working round the circle builds the relationship between neighbouring keys, which is genuinely useful. Random drawing stops you from unconsciously avoiding the four keys you find hard, which is the failure mode most players have.

Why does G♯ major have a double sharp?

Its seventh degree has to be a kind of F, and it needs to sit a semitone below G♯, which is F double sharp. The key is legal and nobody writes in it — A♭ major has the same sounding notes and four flats instead of eight sharps.

Does it include harmonic and melodic minor?

Harmonic minor is included, alongside major and natural minor. Melodic minor is not in the draw — it traditionally differs going up and coming down, which does not fit a single note list cleanly.

Random Scale Generator

Picks a scale for you to practise and spells it out properly. Every scale here is calculated from its tonic rather than looked up, so you get B♭ where a piece of music would write B♭ and A♯ where it would write A♯ — the distinction a pitch-number generator throws away and a teacher immediately marks wrong.

Scale families

Major and minor

Modes

Pentatonic

Blues

Draw from all tonics, including theoretical keys

Seed (optional)

A word or phrase makes the draw reproducible: the same word with the same settings gives the same result, so use a new word for each question.

Your scale will appear here.

What this generator does

Gives you a scale to work on, chosen at random from the types you allow, and prints the notes in order with their degree numbers and the key signature that goes with it. The point is that it is calculated: the scale is built by walking up the letter names from the tonic and works out what accidental each one needs to land on the right interval. That is why F major comes out F G A B♭ C D E and not F G A A♯ C D E, and why G♯ major genuinely needs an F double sharp — a fact the tool tells you, along with the suggestion to write it as A♭ major instead.

How to use this tool

Choose which scale types you want in the draw — major, natural minor, the modes, pentatonic, blues.
Choose whether to draw from practical keys only, or from all seventeen tonic spellings including the awkward ones.
Press Draw scale.
Practise it ascending and descending, then draw again.

Understanding the controls

Scale types: Which families are in the draw. Major and natural minor are the exam staples; the modes (Dorian, Phrygian, Lydian, Mixolydian, Locrian) are the same seven notes started in different places and sound quite different; pentatonic and blues scales drop notes rather than add them.
Key range: Practical keys are twelve tonics that appear in real music. As major or minor keys none has more than six sharps or flats; some modes and blues scales on them — D♭ Phrygian, F♯ Lydian, A♭ blues — still need seven or more. All tonics adds the theoretical keys like G♯ major and D♯ major, which need double sharps and exist mainly to be argued about.
Seed: Makes the draw reproducible: the same word with the same boxes ticked gives the same scale, so a different word is needed for each scale you want to set.

Worked examples

Major and minor only, seed round9: A harmonic minor: A B C D E F G♯. Key signature: no sharps or flats — the raised seventh, G♯, is written into the music rather than the signature.
Modes only, seed round9: C Mixolydian: C D E F G A B♭. Key signature: 1 flat — B, the signature of F major, whose fifth degree the mode starts on.
Pentatonic only, seed round9: A minor pentatonic: A C D E G. Key signature: no sharps or flats. Five notes, so two letter names are skipped.
Blues only, seed round9: C blues: C E♭ F G♭ G B♭. Key signature: 3 flats — B E A, the minor key on the same tonic; the G♭ is written in as an accidental, so the letter G appears twice.

Common use cases

A daily warm-up that does not always start on C
Grade-exam scale practice, where the examiner will pick and you cannot
Working systematically through the modes without choosing favourites
A guitar or bass player learning positions across the neck
A teacher setting a different scale for each student in a group lesson

How this generator works

A scale type is a pattern of semitone intervals from the tonic — major is 0, 2, 4, 5, 7, 9, 11 — paired with a pattern of letter steps. Starting from the tonic's letter, the letter pattern is stepped up for each degree, and then chooses the accidental that makes that letter land on the required semitone. Because the letter is decided before the accidental, each letter name is used once and only once in a seven-note scale, which is what correct notation requires. The key signature is read off the spelled scale — whichever letters carry a sharp or flat, a double counting twice — and written in the conventional F-C-G-D-A-E-B order for sharps, reversed for flats.

Randomness and fairness

The tonic and the scale type are chosen by the browser's cryptographic random number generator, so successive draws are independent — the same scale can come up twice in a row, and over a long session it will. Nothing about the spelling is random; once the tonic and type are drawn, the notes follow deterministically from music theory. A seed switches to a reproducible, non-cryptographic generator: the same word with the same boxes ticked gives the same scale every time, so several students can be set the same one.

For how randomness is produced across the whole site, see how Generate Random works.

Limitations and good to know

There is no audio and no notation image — the output is note names, degree numbers and a key signature, which is what fits in a practice notebook.
It does not know your instrument, so it will offer scales that are awkward on a beginner's flute or in first position on a guitar.
Fingerings are not included, because they differ by instrument, by level and by teacher.
Blues and pentatonic scales have more than one accepted spelling in some keys; the tool picks the one that keeps letter names in order and says so where the result is unusual.
Choosing 'all tonics' will hand you keys nobody writes music in. That is deliberate for theory drilling, and a bad idea for practice.

Common mistakes

Writing a scale with a letter name used twice: A seven-note scale uses each of A to G exactly once. If you have written both A and A♯, one of them is spelled wrong — that is the check this tool is built around.
Assuming the relative minor has a different key signature: It has the same one. A minor and C major both have no sharps or flats; what differs is which note the music treats as home.
Practising only ascending: Descending is where the fingering problems live, and it is half of what an examiner asks for. Play both every time.
Treating the modes as exotic: D Dorian is the white notes from D. If you can play C major you can already play all seven modes — what changes is where the music rests.

Practical tips

Draw three scales at the start of a practice session and work through them properly rather than drawing repeatedly until you get an easy one.
Say the degree numbers out loud as you play; it makes the chord work in the progression generator much easier later.
If a scale comes up with more than four sharps or flats, play it slowly and name the notes before touching the instrument.

Privacy and your data

Nothing is entered and nothing is stored. The draw happens in your browser, no scale you generate is uploaded or written into the page address, and analytics records only that the tool was used — never what was drawn.

Frequently asked questions

Why does F major show B♭ instead of A♯?: Because they are the same key on a piano and different notes in music. A major scale uses each letter name once: F, G, A, then a kind of B, then C, D, E. Calling it A♯ would use A twice and skip B, which makes the key signature impossible to write and the sheet music harder to read.
What is the difference between a mode and a scale?: A mode is a scale — the word usually means one of the seven scales you get by starting the major scale's notes on each of its degrees. D Dorian, E Phrygian and A Aeolian all use the white notes, but each treats a different note as home, and that changes which intervals sit above the tonic and so how the scale sounds.
Should I practise scales from the circle of fifths instead of at random?: Both have a place. Working round the circle builds the relationship between neighbouring keys, which is genuinely useful. Random drawing stops you from unconsciously avoiding the four keys you find hard, which is the failure mode most players have.
Why does G♯ major have a double sharp?: Its seventh degree has to be a kind of F, and it needs to sit a semitone below G♯, which is F double sharp. The key is legal and nobody writes in it — A♭ major has the same sounding notes and four flats instead of eight sharps.
Does it include harmonic and melodic minor?: Harmonic minor is included, alongside major and natural minor. Melodic minor is not in the draw — it traditionally differs going up and coming down, which does not fit a single note list cleanly.