Gauge is the diameter of a string in thousandths of an inch (0.001"). For example, a 9-gauge string has a diameter of 0.009". Guitar strings come in a variety of gauges from extra super light to extra heavy. Gauge affects both the tone and playability of the instrument.

 

Heavier gauge strings produce a richer, louder tone and hold their tuning longer. They are also at a higher tension. As a result, they vibrate in a shallower arc, which allows closer adjustment to the fingerboard without string buzzing. However, the higher tension means that more pressure must be applied to fret the string, which demands more strength in the fingers. A general rule is to use the heaviest gauge with which you're comfortable.

 

Be aware that heavier gauge strings pull harder on the neck of a guitar and may cause it to bow. This can be countered by adjusting the truss rod. For a heavier string gauge, the truss rod needs to be tightened by about 1/8th of a turn. (Never turn it more than 1/4 or the guitar could be permanently damaged.) Consult an expert if uncertain.

 

Generally, factory guitars come are strung with 12–54 gauge on acoustic guitars and 9–42 on electric guitars. Altering string gauge may require adjustment to your guitar to maintain a similar action. And remember lower string tension will cause the strings to lie lower which may result in buzzing.

 

Acoustic guitar string gauges

 

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

 

Electric guitar string gauges

 

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	.011	.016	.026	.036	.046
Medium (11–49)	.011	.014	.018	.028	.038	.049
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