The acoustic guitar scale length

The guitar scale length is one of the variables that must be considered when you are choosing your own instrument, and it consists of the total length of the vibrating string.

It is measured starting from the nut internal side up to the point where the E string (the thinnest) comes into contact with the bridge on the harmonic case. The part of the strings between the nut and the headstock mechanics and the part fixed beyond the bridge should not be considered.

The scale length is measured in inches or millimeters. The guitar scale should not be confused with musical scales.

Standards for guitar scale length

For centuries luthiery was a craft art, there were no standards until the advent of the industrial production.

With the standardization of the instruments, two standards have been established for the acoustic guitar scale length. There are the long-scale instruments with a 25.50″ scale length, equivalent to 647.70 mm, and the short-scale with a 24.75″ scale length, equivalent to 628.65 mm.

Fender Stratocaster is perhaps the most famous example of long-scale guitar; Gibson Les Paul is instead a typical short-scale model.

However, there are also intermediate measures such as the PRS with a scale of 25.00″, equal to 635.00 mm; these are having a considerable commercial diffusion.

In general, the more widespread scale length in folk guitars is between 610 mm and 660 mm.

There are also instruments with a smaller scale length, such as the 24.00” or 609.60 mm of the Fender Duo-Sonic; or higher as the 34.00″ or 863.60 mm of the Long-Scale Bass.

The link between the fretboard and the guitar scale length

The guitar scale length is used to determine the exact arrangement of the frets along the instrument neck.

Dividing the scale length measure for 17,835 we will obtain the distance to hold between the nut and the first fret. To calculate the distance between the first and the following fret, the residual length is always divided by 17.835 and this continues until the last fret.

It will happen that the twelfth fret will be exactly in correspondence with the half of the scale length and the seventh fret will be positioned at two-thirds of the distance between the nut and the twelfth fret.

Because of the use of this value, this method is called the eighteen rule.

Obviously, this work will be carried out by the instrument manufacturer or by your trusted lutist, who with his experience will be able to round the decimal figures without compromising the arrangement of the frets.

Having a shorter or longer fretboard, depending on the guitar scale length, involves a different distance between the various frets: Holdsworth chords are easier to perform on a short-scale instrument; instead, only the twentieth fret will be easier to obtain playing a long-scale guitar, especially if your hands are particularly large.

If you want to know more about the characteristics of the guitar fretboard, read this article.


Il diapason della chitarra acustica

The influence of the scale length on the guitar sound

The scale length is important because it influences the tension of the strings and consequently the sound and the feeling of the artist with the fretboard.

With the same string diameter and tuning, the string tension increases proportionally with the increase in the scale length size.

The measure of the guitar scale length influences the instrument timbre in a decisive way: for example, a string stretched more because on a long scale it gives us a tighter, more present and faster sound in the attack.

In addition, as the strings of a long scale instrument vibrate more, with a major scale length also the acoustic guitar sustain improves.

As usual, the best way to understand the differences between long and short-scale instruments is to try two different guitars with your own hands and appreciate the difference under your fingers.

Taking as reference the two instruments mentioned above, we will observe that intoning the same bending with the Gibson Les Paul will be simpler, it will take less force due to the lower tension of the short scale.

Instead, it will be difficult to get a wild vibrato on the Fender Stratocaster as its pitch change will be affected by the long scale.

In general, the short-scale guitars offer a greater sense of playability: they are easier to use because of the strings lower tension, but in the end, the difference between the two different sizes can be reduced to a stylistic issue.

There is no better scale than the other, there is not an optimal scale length: with the right awareness of the effects that the scale produces on sound and on playability, you will be able to choose the right instrument for our musical inclinations and your guitarist skills.

[Photo Credits: Brian, Don’t Fret Productions]