Writing Chromatic Scales: The Ultimate Guide

By Michael Q. Klein

Chromatic scales are not hard to understand. You go from a note to the same note an octave higher — or lower — in semitones. That is the whole idea. There is nothing to work out by ear and nothing to memorise.

What is confusing is knowing which ways of writing them count as correct. That question matters most in the ABRSM Grade 5 Theory exam, section 3.6 (a and b), where you are shown two chromatic scales and asked whether they have been written correctly.

I wrote this blog because I was trying to find the exact rules for which ways of writing chromatic scales count as correct — concise and comprehensive. But after reading page after page on the Internet, I still felt my mental picture was incomplete, confused, and riddled with contradictory information. So I went back to the ultimate source of truth: the pink book (ABRSM's The AB Guide to Music Theory, Part I). The point of this blog is to take that short section of the book and make what it says more accessible, and work it through more examples so we can really see what it means — the rules of the book, but more examples, longer and clearer explanations.

Approach 1: the harmonic chromatic scale

The book tells us: "theorists distinguish between two ways of writing the chromatic scale: the harmonic and the melodic. The harmonic chromatic scale is the same whether ascending or descending, or whether it occurs in a major or in a minor key."

One spelling, both directions, no exceptions. Write it ascending and you have already written it descending — just read it backwards.

It works like this: every note is spelled as a named interval above the tonic, and the list of intervals never changes.

• Tonic
• Minor 2nd
• Major 2nd
• Minor 3rd
• Major 3rd
• Perfect 4th
• Augmented 4th
• Perfect 5th
• Minor 6th
• Major 6th
• Minor 7th
• Major 7th
• Tonic

Thirteen intervals, thirteen notes. Learn that list once and you can write a harmonic chromatic scale in any key.

Look at what it does to the degrees of the scale, because two of them behave unusually:

• Degrees 2, 3, 6 and 7 each appear twice, once minor and once major.
• Degree 4 appears twice as well, but as a perfect 4th and an augmented 4th. It gets raised, not lowered.
• Degree 5 appears once. The dominant is never altered. There is no flattened fifth in a harmonic chromatic scale.
• The tonic appears once at each end, unaltered.

If you remember one thing from this section: the fourth is the degree that gets sharpened, and the fifth is left alone.

C

Applying the recipe to C: the minor 2nd above C is D♭, the major 2nd is D, the minor 3rd is E♭, the major 3rd is E, the perfect 4th is F, the augmented 4th is F♯, the perfect 5th is G, the minor 6th is A♭, the major 6th is A, the minor 7th is B♭, and the major 7th is B.

Ascending

Descending

The descending stave is the ascending one backwards, note for note. Check it against the hard rules: thirteen notes, C at both ends, and the letters run C–D–D–E–E–F–F–G–A–A–B–B–C, so every letter appears and none appears three times. Notice that G, the fifth, is the only letter that turns up just once.

G

Ascending

Descending

The augmented 4th above G is C♯, and D — the fifth — is again the lone letter.

F

Ascending

Descending

Two spots here catch people out. The minor 2nd above F has to be a second, so it must be a G of some kind: G♭, not F♯. And the augmented 4th above F is B natural, which looks bare sitting between B♭ and C but is exactly right.

A♭

Now the awkward ones. Because the harmonic form follows intervals rather than convenience, remote keys produce spellings that look like mistakes.

Ascending

Descending

Yes, that is a B double flat on the second note, and yes, it is correct. A minor 2nd above A♭ has to be a B of some kind, and A♭ to B♭ is a major second — so the minor second can only be B♭♭. The same logic gives you C♭ for the minor 3rd and F♭ for the minor 6th. Run the hard rules over it and it passes cleanly: thirteen notes, A♭ at both ends, every letter present, no letter three times in a row.

You will find versions online that quietly swap the B♭♭ for an A natural to dodge the double flat. That spelling passes all four hard rules too, so you could not call it wrong — but A natural is an augmented unison above A♭, not a minor second, so it is no longer the strict harmonic chromatic scale. If you are writing one, follow the intervals.

F♯

Ascending

Descending

Sharp keys behave better than flat keys here: F♯ needs no double accidentals at all. It does need B♯ for the augmented 4th and E♯ for the major 7th, and both look wrong on the stave until you remember that the augmented 4th above F♯ must be some kind of B, and B♯ is the only candidate.

Push further and double sharps become unavoidable. In C♯, the augmented 4th above the tonic is F double sharp. That is not a trick — it is simply what the interval is called.

Does the key signature matter?

Chromatic scales are sometimes printed with a key signature. For the harmonic chromatic scale this changes nothing at all.

The reason is that the harmonic form is already built on a key centre. And here is the part that surprises people: the harmonic chromatic scale of C major and the harmonic chromatic scale of C minor are identical, and so is the one starting on C with no key signature at all. There is one harmonic chromatic scale per starting note, and it serves the major and the minor key together.

What a key signature does change is how many accidentals you have to write. Here is the same C harmonic chromatic scale as above, printed with a key signature of three flats:

Nine written accidentals have become six: the key signature supplies E♭, A♭ and B♭ for free, and in exchange you write naturals to cancel them. Same thirteen sounds, same thirteen letters. The scale did not change; only the bookkeeping did.

Approach 2: the melodic chromatic scale

The melodic chromatic scale does the opposite. It spells notes according to where the music is going, which means it looks different ascending and descending.

The principle is: fill the gaps, raising on the way up and lowering on the way down. Start from the notes of the scale you are in, then plug each whole-tone gap with one extra note — sharpened going up, flattened coming down — choosing spellings that keep the four hard rules and avoid double accidentals.

Where a semitone already exists between two letters, you need nothing at all. That is why a chromatic scale on C has no E♯ and no B♯ going up: E to F and B to C are already semitones. Coming down, those same two gaps mean you never need F♭ or C♭.

This is the form you meet in real music. When a composer writes a chromatic run they write it melodically, because sharps going up and flats coming down is far easier to read at speed. It is also the form the Grade 5 paper prints in section 3.6.

In key and out of key

This is where the internet falls apart, so let me be precise about it.

Out of key means no key signature is printed, so every accidental you need is written in front of its note. You spell by direction from the starting note: sharps ascending, flats descending, with naturals wherever the semitone is already there.

In key means a key signature is printed, and two things change. First, you only write the accidentals the key signature does not already give you, plus naturals to cancel the ones it does. Second, and more interesting, the notes of the key become your skeleton — so wherever there is a genuine choice of spelling, you take the one that belongs to the key.

Most of the time both routes land on exactly the same notes. Occasionally they differ by a single note, and that single note is why you will find two different "correct" answers for the same scale on two different websites. Neither is lying. They are anchoring to different things.

C

In C the two routes agree completely, which is why C is the example everybody uses.

Ascending

Descending

Ascending, every gap is filled with a sharp, and E and B stand alone on the stave because their semitones come for free. Descending, the flats mirror it exactly, and this time F and E are the ones standing alone. Letters ascending: C–C–D–D–E–F–F–G–G–A–A–B–C. All seven present, none three times.

G

Ascending — identical in key and out of key:

Descending, out of key

Descending, in the key of G

One note apart. Out of key the direction rule says flatten, so you get G♭. In the key of G, F♯ is a note of the key and sits in the skeleton already, so you keep it — and because the key signature supplies the sharp, the second note carries no accidental at all while the third needs a natural. Both versions pass all four hard rules, and both are correct in their own context.

F

Ascending, out of key

Ascending, in the key of F

A♯ or B♭: same sound, and the key signature decides. In F, B♭ belongs to the key, so the in-key version uses it — and gets it from the key signature for nothing.

Descending — identical in key and out of key:

A♭

With A♭ and F♯ the "sharps up, flats down" shorthand stops being much use, because the tonic itself is already altered. Rule 2 forces you to begin and end on A♭ rather than G♯, and the key's own notes take over as the guide.

Ascending

Descending

Notice how much tamer this is than the harmonic version: no double flats, no C♭, no F♭. The melodic form can avoid them because it is free to pick whichever spelling reads best, while the harmonic form is locked to the intervals.

Printed with the A♭ major key signature, the same ascending scale drops from ten written accidentals to five:

Four naturals and one sharp, and the closing A♭ needs no accidental of its own — the key signature supplies it, and the A natural earlier in the bar was an octave lower.

F♯

Ascending

Descending

Look at that descending stave: not one flat in it. That is the clearest proof that "flats descending" is a rule of thumb built around C, not a law. In F♯ there is nothing to flatten — you spell downwards using naturals to cancel sharps.

E♯ is the note people query. In the key of F♯ it is the leading note, so it belongs, and you need something between E and F♯. Out of key you will also see F natural used there, which passes the hard rules too, but E♯ is the spelling that keeps faith with the key.

Compare F♯ melodic with F♯ harmonic and they differ by exactly one note in each direction: melodic uses C where harmonic uses B♯. Everything else is the same. In the sharpest keys the two approaches very nearly converge.

The four hard rules

Whatever approach you use, there are four rules that every correctly written chromatic scale has to satisfy. Break one of these and the scale is wrong, no discussion. These four alone will settle most section 3.6 questions.

• 1. Thirteen notes. A one-octave chromatic scale has twelve semitone steps, which means thirteen written notes: the starting note, eleven notes in between, and the starting note again at the other end.
• 2. It must finish on the exact note it started on. An octave higher or lower, spelled the same way. A scale that begins on G♯ must end on G♯, not A♭. They sound identical, but as a written answer A♭ is wrong.
• 3. Never more than two of the same letter name in a row. D♭ – D – D♯ is three D's, so it is wrong no matter how right the pitches sound.
• 4. Every letter name must appear at least once. All seven letters — A, B, C, D, E, F and G — have to turn up somewhere. Skip one and the scale is wrong.

Rules 3 and 4 do most of the work, and they are really two halves of one idea. Thirteen notes spread across seven letter names means some letters must be used twice; there is no way around it. What the rules forbid is doing it unevenly — no letter three times, and no letter left out. That constraint alone eliminates most of the wrong answers you will be shown.

Rule 2 is the one students dismiss as a technicality, and it is the one examiners love. G♯ and A♭ are the same key on the piano, so a scale that starts on G♯ and finishes on A♭ sounds perfect. On paper it is a different note, and it fails.

Everything else worth knowing

The leftovers. None of them is big enough for a section of its own, and every one of them can cost you a mark.

• What 3.6 actually asks. You are not asked to write a chromatic scale from scratch, and you are never asked to name the harmonic or the melodic form. You get two true/false items, 3.6a and 3.6b, each showing a printed chromatic scale, and you decide whether it has been written correctly. Usually one ascending and one descending.
• The twenty-second check. Count the notes; there should be thirteen. Compare the first and last note — same letter, same accidental. Read the letter names aloud and listen for a triple or a missing letter. Then check the accidentals match the direction. That sequence catches almost every planted error.
• Say the letters out loud. Your ear notices a gap in the alphabet long before your eye notices a gap on the stave. "C, C sharp, D, D sharp, E, F…" is faster and far more reliable than staring at the notation.
• Accidentals last to the end of the bar — but only for that note in that octave. This matters enormously here, because the same letter keeps returning in two forms. In C harmonic chromatic you write E♭ and then E, and that E needs a natural sign or it is still an E♭. Same for D♭ to D, A♭ to A, and B♭ to B. But an A♭ low in the bar does not flatten an A an octave higher, which is why the closing note of a scale so often carries its own accidental.
• Where the accidental sits. Immediately before the notehead, on the same line or in the same space. Not after it, and not on a neighbouring line. Examiners do plant this one.
• Double accidentals are not errors. B♭♭ in A♭, F double sharp in C♯ — these are what the intervals demand in remote keys. Seeing one is no evidence that a scale is wrong.
• Watch the clef. Grade 5 uses four clefs, and a chromatic scale can be printed in the alto or the tenor clef. Every stave above is in the treble, but the rules do not change — only your reading speed does. If your C clef reading is slow, a scale you would spot instantly in the treble becomes a guess, and that needs fixing separately.
• Note values and beaming. A chromatic scale is written in equal note values, usually quavers or crotchets, and these questions carry no time signature. If one is given, beam according to the beat.
• Enharmonic equivalents are a different question. Knowing that G♯ and A♭ are the same pitch is section 2.2. Knowing that a scale starting on G♯ must end on G♯ is section 3.6. The paper tests both, and the second one punishes you for getting too relaxed about the first.
• You are probably already playing them. Chromatic scales appear in the ABRSM practical requirements from Grade 2 upwards. Playing one while naming the letters aloud is the fastest way to make the written pattern stick, and our Scales and Arpeggios trainer follows the ABRSM parameters for Grades 1 to 8, including chromatic scales in similar and contrary motion.
• Why any of this exists. Composers use chromatic notes constantly — as passing notes, as approach notes, as whole runs. The spelling conventions exist so that a performer reading at speed can tell instantly which way the line is heading. That is the entire purpose. It was never designed to test you; it was designed to make the page readable.

Train it, then test it

On Play Music From Within the Grade 5 suite has a dedicated trainer for chromatic scales alongside every other exam subsection, with unlimited generated questions and a worked explanation after each one. It also tracks your accuracy per subsection, so you can see whether 3.6 is genuinely secure or just occasionally lucky.

When you want the real thing instead of a drill: Sign in to take your free full mock exam — a complete paper in exam order with explanations as you go. Prefer it under pressure? Sit a timed session that scores you at the end like the live exam.

Not sure where you stand yet? The free readiness check takes a few minutes and gives you a personalised practice plan, so you train the weak sections instead of the comfortable ones.

Keep going: What's in the ABRSM Grade 5 Theory Exam? maps every section of the paper, and How to Pass ABRSM Grade 5 Theory is the full preparation route.