Accordion Sizes: 8 to 120 Bass Explained
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The number in an accordion's name - 48 bass, 72 bass, 120 bass - counts the buttons on the left hand side, and it's one of the standard shorthand for how big the whole instrument is. The common sizes are 48, 72, 96 and 120 bass, running from just under 5kg over to 15kg and from 26 treble keys up to 41. Smaller instruments of 8 to 32 bass exist for children and for melodeon-style playing. Larger sizes than 120 are specialist.
Size determines three things at once: how many chords you can play, how many treble keys you get, and how much the instrument weighs.
What the bass number actually means
The left hand side of a piano accordion usually laid out in the Stradella bass system: rows of buttons giving you bass notes and ready-made chords. The number counts every button on that side.
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They're arranged in a fixed pattern, so a 120 bass instrument doesn't do anything a 72 bass one can't - it does the same thing in more keys. The two outer rows give single bass notes; the inner rows give major, minor, seventh and diminished chords.
In practical terms: more buttons means more keys you can play comfortably without awkward reaching. If you play mostly in a handful of common keys, 72 bass covers you. If you're reading arrangements written for full-size instruments, or accompanying in unusual keys, you'll want more.
Sizes at a glance
Real figures from our current stock. Weights are the actual instruments on our floor, not manufacturer estimates.
The small sizes: 8 to 32 bass
8 bass is not really a piano accordion size at all - it's the standard for diatonic melodeons, where the left hand gives you a small number of bass and chord buttons suited to folk and traditional playing. Light, typically 3 to 4kg.
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15 bass instruments are a modern development aimed at portability and young players. The lightest things we stock, under 3kg.
24 and 32 bass are children's piano accordions. They have proper piano keyboards, usually 30 keys, and a working if limited chord set. Around 5 to 6kg - which surprises people, because they don't feel small once they're strapped on.
48 bass
The smallest size with a genuinely complete chord set. Usually 26 treble keys, occasionally 30. Our current stock runs 4.9 to 6.8kg.
Suits: smaller adults, older children moving up from a 24 or 32, adults with back or shoulder problems, and anyone who wants to be certain weight won't become an obstacle.
The limitation: 26 treble keys is just over two octaves. You'll meet the edges of it eventually, particularly with anything written for full-size instruments.
72 bass
The most popular size in Britain, and for most adult beginners the sensible default. Usually 34 treble keys, with compact 26 and 30 key versions for players who want the bass range without the width. Our stock runs 4.9 to 9.7kg, averaging 7.5kg.
Suits: the majority of adult players. Enough chord range for most repertoire, enough treble range for most arrangements, and a weight most people can manage for a full practice session.
Worth knowing: the spread within this size is wide. A compact 26 key 72 bass can weigh under 5kg; a four voice 34 key one nearly 10kg. If weight matters to you, the compact versions are the ones to look at.
96 bass
A genuine middle ground: 34 or 37 treble keys, 7.3 to 11.9kg, averaging just under 10kg.
Suits: players who know they're committed, and anyone who wants close to full-size range without full-size weight. This is where a lot of players settle permanently.
Worth knowing: the 34 key compact models are the interesting ones. You keep the full 96 bass chord range while losing the width and some of the weight of a 37 key instrument. If you like the idea of a 120 but not the reality of carrying one, this is the size to try.
120 bass
The full-size instrument, and the one most people picture. Traditionally 41 treble keys, though 37, 39 and 45 key versions exist. Our stock runs 8.0 to 15.9kg, averaging 11.3kg.
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Suits: committed and professional players, anyone reading repertoire written for full-size instruments, and players who need the complete range of couplers and tunings - which is widest at this size.
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The full chord range is genuinely useful, but only if you can play the instrument for as long as you want to without discomfort. An 11kg accordion you avoid picking up is worth less than a 7kg one you play daily.
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Worth knowing: the lightest 120 bass in our stock is 8kg, lighter than several of our 96 bass instruments. Compact 120 bass models with 37 or 39 keys exist specifically for players who want the range without the bulk, and they're worth asking about.
Above 120 bass
132 bass and larger instruments, and converter or free bass models, extend the left hand into a full chromatic scale rather than fixed chords. These are specialist instruments for classical and advanced repertoire. If you need one, you already know.
How to choose between sizes
Work through these in order.
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1. What can you comfortably carry?
Not lift once - hold and play for forty minutes.
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2. What do you want to play?
Folk and traditional playing often needs less bass range than you'd expect. Continental, classical and arranged repertoire needs more.
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3. How big are your hands, and how long is your reach?
The treble keyboard width matters as much as the weight. Someone with a shorter reach may be far happier on a 34 key instrument than a 41.
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4. Do you play sitting or standing?
Standing for hours at ceilidhs and dances changes the answer substantially.
Common questions
The number counts the buttons on the left hand side - 48 bass has 48 buttons, 120 bass has 120. It usually is standard shorthand for the instrument's overall size, and it can indicates the treble key count and the weight too.
Your own size matters more than anything else when choosing. An accordion sits against your chest with its full weight on your shoulders, so the right instrument is the one that fits your frame and your reach
Roughly: 48 bass has 26 keys, 72 bass has 34 (or 26 to 30 in compact form), 96 bass has 34 or 37, and 120 bass has 41. There are exceptions in both direction
Yes, and many players do. We take instruments in part exchange against anything in stock, which makes moving up considerably cheaper than most people expect.
Not inherently. Larger instruments usually have more reed sets and more coupler options, so they're more versatile - but a well-made 72 bass will sound better than a poorly made 120.