The Importance of String Gauges

While the tone of a string has a lot to do with its type – such as flatwound or roundwound – it also has a bit to do with its weight, and therefore, its diameter, which we know as its gauge. For the most part, we tend to describe a string’s gauge by the measurement of its diameter in thousandths of an inch (where 0.001 in = 0.0254 mm). The larger the diameter, the heavier the string – not too difficult in that department.  And as to be expected, heavier strings require more tension to reach the same pitch as compared to lighter strings, meaning a heavy gauge E string will have to be strung tighter than a lighter gauge E string to be in tune. And as a consequence of having to be strung tighter, are harder to press down on a fingerboard which also makes nailing down bends a bit tougher.

Another consequence of using heavier strings is that you have to make sure your guitar’s intonation is adjusted to compensate for the added tension of tighter strung strings. Same thing is true if you’re going from heavy to light as well. The neck on a guitar is not as straight as most non-musicians tend to believe as it actually curves a bit, much like a bow, in order for the strings to be able to hover above the frets (a perfectly straight neck would result in the strings lying flat on the fingerboard). When tension is added to the neck – such as by adding a heavier set of strings – the added pull can cause the neck to bend inward, resulting in much higher action which in turn makes it a pain to play. Switching from heavy strings to a lighter gauge on the other hand can cause the neck to relax, resulting in a straighter bow which can lead to fret buzzing from the strings constantly touching the fret wire. In either case, the intonation must be fixed in order to restore playability which can be done by adjusting the truss rod in the neck along with changes to the bridge to compensate for chances in the action. It’s not as tough as it sounds if you have experience but newbies should really get a pro to do this for them as any major mistake – especially with the truss rod – can result in permanent damage to your guitar.  

As far as tone goes, the general consensus will tell you that higher-gauged strings (thicker) will yield a fatter, louder, more compressed tone while lighter string gauges will result in a thinner, brittle or weak tone. While there is a bit a truth to that, we all know that tone isn’t the result on one single thing but rather an interaction of all of your pieces. That is to say that if you were looking to drastically change your tone, simply increasing the gauge won’t make much of a difference, not nearly as much as changing the type of string, anyways. But since we are talking purely about the gauge of a string and tone, thinner strings equal thinner sound and fatter strings equal fatter sound.

Another interesting little tidbit about the effects of the gauge of a string has to do with harmonic content. As mentioned above, heavier strings need to be tighter than light strings to create a given pitch. It also happens that tighter strings produce stronger harmonics. As a result, this means that heavier strings have tend to have a brighter, clearer, livelier tone than lighter strings.

Heavier strings also naturally sustain longer than thinner strings but also interact with the magnets in the pickups more, dampening the sustain. Interestingly enough, the added sustain from the heavier string tends to approximately balance out the loss of sustain from the extra magnetic interaction, resulting in a string that pretty much has the same amount of sustain that it started with – but that doesn’t mean that the end result in tone is the same. Because this energy is in a closed system, the decrease in sustain caused by the magnetic interaction of the pickups is effectively changed into an increase in voltage. The extra material of the heavier strings causes more voltage to be inducted into the pickup coil which those familiar with hot pickups already should know, results in a louder output. Of course, you can always manually lower your pickups to reduce the magnetic interaction in order to keep some of that extra sustain brought by the heavier strings. Alright, now let’s take a look at some common string gauges.


*Note: The sample data below comes from D'Addario string charts for regular, round-wound, nickel-plated strings.


Electric guitar

(Note: D, A and low E strings are always wound. G can be plain or wound depending size of gauge or manufacturer.)

Name 1 (E) 2 (B) 3 (G) 4 (D) 5 (A) 6 (E)
Extra super light (8-38) .008 .010 .015 .021 .030 .038
Extra super light plus (8.5-39) .0085 .0105 .015 .022 .032 .039
Super light (9-42) .009 .011 .016 .024 .032 .042
Super light plus (9.5-44) .0095 .0115 .016 .024 .034 .044
Regular light (10-46) .010 .013 .017 .026 .036 .046
Extra light w/heavy bass (9-46) .009 .013 .016 .026 .036 .046
Medium (11-48/49) .011 .014 .018 .028 .038 .048/49
Light Top / Heavy Bottom (10-52) .010 .013 .017 .032 .042 .052
Medium w/wound G string (11-52) .011 .013 .020 .030 .042 .052
Heavy (12-54) .012 .016 .020 .032 .042 .054
Extra heavy (13-56) .013 .017 .026 .036 .046 .056

(Diameter in mm)


Acoustic guitar

(Note: As with electric guitar strings, D, A and low E are wound. All others are plain, with some exceptions for G. These are for steel string guitars, not classical nylon/gut strings.)

Name 1 (E) 2 (B) 3 (G) 4 (D) 5 (A) 6 (E)
Extra light (10-47) .010 .014 .023 .030 .039 .047
Custom light (11-52) .011 .015 .023 .032 .042 .052
Light (12-53) .012 .016 .025 .032 .042 .053
Light/Medium (12.5-55) .0125 .0165 .0255 .0335 .0435 .055
Medium(13-56) .013 .017 .026 .035 .045 .056



Bass guitar

Bass guitar strings are sometimes made for a particular scale length and come in short, medium, long and extra long (sometimes called super long) scale. Typical bass guitar strings come in the following gauges:

Name 1 (G) 2 (D) 3 (A) 4 (E) 5 (B)
Light or "soft" (40-100) .040 .060 .080 .100 .120
Medium (45-105) .045 .065 .085 .105 .125
Heavy (50-110) .050 .075 .095 .110 .130

Note that some string manufacturers produce other sets of strings. The figure above merely lists the most common combinations. Sometimes, they use combinations of the numbers above. For example, a manufacturer might use a .045 and a .065 (both from Medium) for the G and D strings, respectively. They might use a .080 and .100 (both from light) for the A and E strings, respectively. For a five-string bass, they might use a .130 (from heavy) for the B string.

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