Buying & Setup

Classical Guitar Scale Lengths, Explained

Why 650mm became the standard, what changes when a guitar is longer or shorter, and how to find the scale that fits your hands.

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What "scale length" actually means

Scale length is the vibrating length of the string — the distance from the nut, at the top of the fretboard, to the saddle on the bridge. It's the part of the string that actually rings when you play. It is not the length of the whole neck or the size of the body, and this trips people up: a guitar can have a small body but a standard-length string, or a full-size body with a shorter scale.

You'll almost always see it written in millimetres, because classical guitars come out of a European luthier tradition. The most common figure by far is 650mm, which works out to about 25.6 inches. When you read a spec sheet, that single number tells you more about how the guitar will feel in your hands than almost anything else on the page.

The reason it matters so much comes down to simple physics. On a longer scale, the string has to be stretched tighter to reach the same pitch, so it feels stiffer under the fingers. It also spaces the frets further apart, so your hand has to travel and stretch a little more. Shorten the scale and the opposite happens: lower tension, a slacker feel, and frets that sit closer together.

How 650mm became the standard

The guitar wasn't always built to one length. In the early nineteenth century, before the modern classical guitar took shape, scales were noticeably shorter — the small Spanish guitars of that era commonly sat around 630mm, and northern European makers in France, Germany and England often built even shorter, around 620mm.

The shift came from Antonio de Torres, the Spanish luthier now regarded as the father of the modern classical guitar. In the second half of the nineteenth century he enlarged the body and lengthened the string to 650mm, chasing more volume and projection so the instrument could hold its own in a concert hall. It worked, and the wider guitar world gradually followed his lead. Scale lengths were never formally standardised the way a piano keyboard is, but 650mm settled in as the common average, and the great twentieth-century makers — Hauser, Fleta, Bouchet, Friederich, Rubio — largely built to it.

Scale length was never standardised the way a piano keyboard was. 650mm simply became the figure that most makers, and most players, quietly agreed on.

The long-scale era

From around the 1960s, the Madrid workshops — José Ramírez chief among them — began building longer, pushing scales out to 664mm and beyond. The argument was more volume, more projection, and tighter intonation, and plenty of players liked the bigger, more powerful sound. For a couple of decades, long-scale instruments were everywhere; Ramírez's famous 1A model shipped with a 664mm scale as standard through that period, and it became the sound of a generation of concert guitars.

That fashion has since receded. Today 664mm and 665mm instruments are much rarer, and 650mm has firmly reclaimed its place as the default. Ramírez, tellingly, now offers its 1A and Traditional models in both scales — you can still order the longer one, but the shorter length is the standard choice. A longer scale is no longer the norm, but it hasn't disappeared, and some players still seek out that firmer feel and fuller projection.

The short-scale movement

Pulling in the other direction, more makers now build shorter scales specifically for comfort and for smaller hands. The common short options are 640mm and 630mm, with some builders going shorter still — 615mm and below — often for younger players or those with a genuinely small reach.

One honest caveat that comes up again and again from luthiers and players alike: the jump from 650mm to 640mm is small. It's only a 10mm difference across the whole string, and many people can barely feel it. If you're chasing a real, noticeable reduction in stretch, 630mm is usually where the difference becomes obvious, and it tends to make itself felt higher up the neck, from around the middle frets onward, where the fret spacing on a long scale asks the most of your hand.

There's a second caveat worth knowing. Because most luthiers build overwhelmingly at 650mm, not every maker has refined their shorter-scale designs to the same degree. The straightforward fix is to buy a short scale from a builder who makes them regularly rather than as a one-off — several specialise in exactly this.

How scale length changes tone and feel

It's tempting to expect a dramatic tonal change from scale length alone, but the truth is more modest. Body size, bracing, wood and the player's own technique all shape a guitar's voice far more than a few millimetres of string. That said, the tendencies are real and consistent:

• Longer scale: higher string tension, a firmer and more responsive feel under the fingers, generally a bit more volume and projection, and a slightly brighter, tighter attack. The cost is wider stretches and a stiffer left hand.
• Shorter scale: lower tension, a softer and slacker feel, easier stretches, and often a warmer, rounder tone — though you may give up a little projection and low-end power in exchange.

Notice that string tension is doing a lot of this work, and tension is something you can also adjust with your choice of strings. A player on a long-scale guitar who finds it stiff can move to lighter-tension strings; a player on a short scale who wants more punch can go up a tension. Scale length sets the baseline, but it isn't the only lever.

One thing many experienced players point out is that a good setup matters more than the raw number. A shorter scale that's poorly set up, with the strings sitting too high off the fretboard, will feel harder to play than a longer scale with a low, clean action. Before blaming scale length for a guitar feeling difficult, it's always worth checking the setup first.

A rough guide by hand size

Scale choice is personal, and the only real test is playing an instrument yourself. But as a starting point, a well-known guideline pairs the span of your hand — measured from thumb tip to little-finger tip, stretched open — with a suggested scale. Treat this as a loose signpost, not a rule:

Thumb-to-pinky span	Suggested scale
250mm and above	664mm (long)
230–250mm	656mm
210–230mm	650mm (standard)
190–210mm	640mm
170–190mm	630mm
below 170mm	615mm and shorter

Take these numbers with a pinch of salt. Plenty of players with modest hands are perfectly happy on a 650mm guitar, and plenty of larger-handed players choose a shorter scale simply because they prefer the feel or want to ease strain. Hand size is a useful input, not a verdict.

So which should you choose?

For most adult players, 650mm remains the sensible default. It's what the overwhelming majority of guitars are built to, it's what most repertoire and most teachers assume, and the huge range of instruments available at that scale means you'll have the widest choice at any budget.

Look seriously at a shorter scale if you have small hands, if long stretches cause you pain or strain, if you're returning to the instrument with an injury, or if you're buying for a child. In those cases, don't stop at 640mm expecting a transformation — consider 630mm, where the difference is genuinely noticeable, and buy from a maker who builds short scales as a matter of course.

Consider a longer scale only if you've played one and specifically loved the firmer feel and bigger projection, and your hands are comfortable with the wider spacing. It's a deliberate choice for a particular sound and feel these days, not a default.

Above all, if you possibly can, play before you buy. A tape measure and a hand-span chart will get you to a sensible shortlist, but scale length is something you feel, not something you calculate. Ten minutes with the actual guitar in your hands will tell you more than any spec sheet.

A guide to classical guitar scale lengths — what the number means, why 650mm is standard, and how longer and shorter scales change the way a guitar feels and sounds.