Overall, acoustic string gauges are classified as the following:

• Extra light
• Custom light
• Light
• Medium
• Heavy

For purposes of this article, we’ll refer to anything from extra light to light as “lighter,” and anything from medium to heavy as “heavier.” While we want this article to be a comprehensive overview of string gauges for acoustic guitars, it is important to note that Martin does not recommend heavy gauge strings for any Martin guitars. We recommend using only extra light through medium gauge strings on our guitars. Heavy strings can cause too much tension on the top, which may cause irreversible damage. 

Why String Gauge Matters 

String gauge isn’t just a number—it shapes how your guitar feels, sounds, and even how long you can play comfortably. A lighter gauge can make your guitar feel more forgiving and easier to play, especially for beginners. Heavier gauges, on the other hand, deliver more volume and sustain, which can be critical for performers who need their sound to cut through a band mix. 

Beyond comfort and tone, gauge directly affects your guitar’s health. Choosing a gauge that’s too heavy can put unnecessary stress on your instrument’s neck and top, while going too light may result in buzzing or reduced projection. Understanding why string gauge matters will help you match the right set of strings to your style, your guitar, and your long-term playing goals. 

Understanding String Gauge 

At its core, string gauge refers to the thickness of a guitar string, usually measured in thousandths of an inch (for example, .010 or .013 for the high E). But it’s more than just a number on a package. Gauge impacts tension, tone, playability, and even how your guitar needs to be set up. 

Smaller-bodied guitars often pair best with lighter gauges because they can’t handle as much string tension, while larger-bodied guitars like Dreadnoughts can support medium gauges for a fuller sound. For players, gauge affects everything from ease of bending notes to how much volume you can project. Knowing how string gauge interacts with your guitar and playing style is the first step toward finding your perfect set. 

Pros and Cons of Acoustic Guitar String Gauges

What's the difference between light and medium guitar strings? How do heavy acoustic guitar strings differ from extra light ones? As you consider the best acoustic guitar string gauge for your needs, you need to understand more about each gauge's pros and cons. Here are factors you should know about:

• Lighter acoustic guitar strings: Lighter acoustic strings include extra light acoustic guitar strings, custom light acoustic guitar strings and light acoustic guitar strings. They are the lightest and easiest strings to play, making them a great choice for beginner guitarists. They have a wonderful, bright tone when played with a soft touch, and their low tension on the neck is good for short-scale acoustic guitars. They also have shorter life spans and have more difficulty holding their tune than heavier strings. Their low volume may make the guitar harder to hear when playing with other musicians.
• Medium acoustic guitar strings: Technically a part of the “heavier” string gauge category, these are the highest tension strings we recommend using on your Martin acoustic guitar. Regarding light vs. medium guitar strings, medium gauge provide a more balanced tone, greater midrange presence and longer life span. Medium guitar strings are still comfortable to play and exert healthy tension on various guitar sizes. Note that lighter guitar strings will capture more high tones than medium gauge guitar strings.
• Heavy acoustic guitar strings: Heavy acoustic guitar strings provide the best low tones, great tuning stability, high volume and increased durability. They generally have the longest life spans. These benefits come at the expense of being harder to play and exerting more tension on your acoustic guitar's neck. Heavy strings also lose some of the top-end sparkle from their tone.

What style of music do you play?

Different genres and techniques often require different string characteristics. 

Lighter Strings 

• Good for rock, folk, country, and blues with a lighter attack. 
• Allow easier bending of notes. 
• May break more easily with aggressive playing. 

Heavier Strings 

• Great for bluegrass or tuning down. 
• Suitable for harder attack in rock, country, and blues. 

What sound are you going for?

Your performance setting matters. 

Lighter Strings 

• Ideal for intimate playing with balanced volume. 

Heavier Strings 

• Produce more projection and sustain. 
• Great when playing with other musicians. 

What Happens if You Change String Gauge?

Switching gauges changes the tension on your guitar: 

• Moving lighter (e.g., medium → light) reduces tension, allowing the neck to relax. This may cause fret buzz due to lower action. 
• Moving heavier (e.g., light → medium) increases tension, making strings harder to fret and raising the action. This can damage guitars not built for heavier gauges. 

Always check the manufacturer’s recommendations before changing the gauge and consider a professional setup to avoid issues like fret buzz or neck bowing. 

Experimenting with String Gauge

If you like the qualities of lighter strings, start with Light and work toward Extra Light or Custom Light if needed. 

If heavier string qualities appeal to you, try Medium first. Remember: Martin does not recommend heavy gauge strings on our guitars. 

Always ensure your guitar is set up correctly for the gauge you’re using. Fret buzz or difficulty in playability may simply mean it’s time for a setup. 

Martin Strings — This Is Why We Make Our Own

Martin Guitar makes our own line of acoustic guitar strings in extra light through medium gauges from a variety of material options to suit every player. All Martin guitars come strung with Martin strings, but they’ll bring out the best tone in any acoustic guitar. 

Browse our complete line of strings here. 

Until next time, happy playing!