How to Choose a Tennis String Gauge

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Much like tennis string tension, choosing a tennis string gauge is a matter of personal preference, with no right or wrong answer.

It’s a case of trial and error until you find something you’re happy with. I always like it when I need to restring my racket, as it gives me an excuse to try out something new.

But, how do we choose a tennis string gauge, and what effect does that have on our shots?

Well, that’s what we’re going to take a close look at today.

Let’s get to it.

What is Tennis String Gauge?

But first, what exactly do we mean when we say tennis string gauge?

The gauge refers to the thickness/ diameter of the string. This is usually depicted in a number ranging from 13-22, which will correlate to a specific range of sizes measured in mm.

Think that sounds confusing? Just wait…

The lower the number, the thicker the string, and the higher number, the thinner the string.

For example, tennis strings with a gauge of 15, will be thinner than 18 gauge strings. It’s a bit counterintuitive, so we’ll break it down in a chart below.

Tennis Guage Sizes

As I just mentioned, brands will depict their gauge as a number between 13 and 22. However, the thickness may vary from brand to brand. Check out the image below to see the difference in thickness between two strings with the same gauge.

tennis string gauge example

In this example, the 16g Head Velocity MLT has a thickness of 1.3mm, whilst the 16g Wilson Sensation plus has a thickness of 1.34mm. While this is only a small difference, it’s worth keeping in mind, especially if you’ve got a specific thickness that you want to use.

With that in mind, it’s important to always pay attention to the mm measurement. This way you can be 100% sure of what you’re getting.

Ok, now that’s all cleared up, below you can see a chart that compares US gauges with their MM range, as well as European/ International gauges. 

US GaugesMMEuropean/ International Gauges
131.65 – 1.80mm12
141.50 – 1.65mm11
151.41 – 1.49mm9.5
15L1.33 – 1.41mm9
161.26 – 1.34mm8.5
16L1.22 – 1.30mm8
171.16 – 1.24mm7.5
181.06 – 1.16mm7
190.90 – 1.06mm4
200.80 – 0.90mm3.5
210.70 – 0.80mm3
220.60 – 0.70mm2.5

Before we go any deeper into string gauges, I just wanted to point out something you may have noticed in the chart above – 15L and 16L gauges. The “L” stands for light and these are slightly thinner versions of that gauge. That said, a 15l will still be thicker than a 16 gauge, however thinner than a regular 15 gauge.

How Does Gauge Effect Performance?

I think it’s worth prefacing this section by mentioning how the string gauge is going to have a minimal amount of impact. If you’re a beginner, I doubt you’d notice the difference between one gauge and another.

That said, the gauge does affect how the racket interacts with the ball, even if it’s not that noticeable at first.

tennis string gauge spectrum

Thin Strings VS Thick Strings

Much like tennis string tension, I like to look at gauge as a spectrum between thick and thin strings.

Thick Strings

A thicker string is going to offer you more control and durability.

Whenever you hit a tennis ball, the strings rub together, causing friction. Over time, this wears away at the strings, causing them to snap. As you can probably imagine, having thicker strings means that it will take longer for them to wear away.

Also, thicker strings will have less flexibility, meaning that although they won’t generate a ton of power, they’ll offer better control than thinner strings.

The downside to using a lower gauge (thicker string) is that and the racket can play slightly stiff.

Thin Strings

Thinner strings are going to give you’re a bit of pop and power in your shots.

As well as this, thinner strings are going to offer much more spin potential compared to thicker strings. This is because the strings will grip and embed themselves into the ball, allowing you to generate more spin. That said, this is only a minimal amount and is not a substitute for good technique. Instead, a thin high gauge will enhance your ability to create spin.

The downside? Durability. Because the strings are thinner, they’re going to wear out quicker than thicker strings. In the long run, this could end up costing you money if you’re having to frequently restring your racket.

Of course, you don’t need to go for one extreme or the other. A lot of players will usually use the middle ground, typically a 15G or 16G as this offers a nice all-round performance.

What Gauge Tennis String Should I Use?


Gauge and string material go hand in hand. If for example, you’ve got a durable string such as polyester, then you can likely use a higher gauge as the strength or the string itself should be able to make up for its thinness.

The same applies the other way as well. If you’ve got a fairly fragile string such as a synthetic gut, a higher gauge will provide the string with a bit more durability. As I’ve mentioned earlier, finding the right gauge is a matter of personal preference, and usually a matter of trial and error until you find something you’re happy with.

In this regard, it’s good to experiment with different strings and gauges until you can find one that suits your play style. That said, I’ll list a few popular string materials and how durable they are:

  • Natural Gut: Not the most common type of string these days. Not very durable.
  • Synthetic Gut: More popular than natural gut, again not known for its durability.
  • Polyester: Nice durable string,
  • Multifilament: Offers a similar feel to the natural gut strings but with a bit more durability.
  • Kevlar: Another extremely durable string.

You can find a useful tool for comparing tennis strings over at the Tennis Warehouse Academy. This will compare the differences in different areas of the strings such as stiffness, tension loss, and spin potential.

Skill Level

As I mentioned earlier, if you’re a beginner tennis player then I wouldn’t worry too much about gauge. I would recommend starting at a 16G and playing with that for a while. From there, you can go either up or down based on your preferences. Go down a gauge if you need more control and durability, and up if you need more power and spin.

A more advanced player, on the other hand, will likely have a better understanding of how they like to play, and how they can utilize tennis strings to enhance their abilities.   

Play Style

At the end of the day, all we want is a racket that’s comfortable to use and matches our needs when it comes to our play style. Below are a few example gauges and what kind of player they would suit.

  • 15G: Very thick string, ideal for players looking for as much durability and control as possible. If you already generate a good amount of power and spin through technique, then a 15G can help with any durability issues you’re likely having.
  • 15L: Thinner than a 15G, but still thicker than 16G. Offers a nice middle ground between the two.
  • 16G: Another fairly thick string, offering slightly more power than 15G. Still ideal for players who are often breaking their strings. 
  • 16L: Thinner than a 16G, but still thicker than 17G. Offers a nice middle ground between the two.
  • 17G: A thin string, great for players looking to generate a good amount of power and spin with their shots.
  • 18G: A very thin string that lacks durability. Ideal for players looking for as much power, spin, and feel as possible.

It’s worth mentioning that there are both higher and lower gauges than those listed above, however, those are pretty niche cases.

How Often You Play

There’s a general rule of thumb when it comes to tennis strings. String your racket as many times a year as you play in a week.

I think this applies here nicely as if you only play once or twice a month, the chances are that durability won’t play much of a factor. With that in mind, you can likely opt for thinner strings, as you won’t be playing often enough to be breaking them frequently.

On the other hand, the more you play, the quicker your strings will start to fray. If you’re a frequent player, then it may be worth going for a slightly thicker string. If the thick string doesn’t complement your play style, you could opt for a softer string to make up for the loss of power.


Whilst feel isn’t necessarily something you can measure, most players will opt for a higher gauge when looking to gain as much feel for their racket as possible. This is because the thinner strings can offer more feedback to the player after each shot.

Does Gauge Effect Tension?

I’ll be honest, it’s hard to know the exact effect that your gauge will have on the tension. You can always use a tool such as the Tennis Warehouse Academy string comparison, but I find the best way is to play and find out.

If you go for a thinner string (higher gauge), and you’re landing your shots out of play often, it could be worth tightening your strings. Conversely, if you’re hitting the net more often than you’re used to, you could try loosening your tension.

Other factors will also come into play when it comes to tension loss, such as how often you play, string material, and when the racket itself was strung.

What Gauge String do the Pros Use?

Roger FedererBabolat VS 16Luxilon ALU Rough 16L
Rafael NadalBabolat RPM Blast 15LBabolat RPM Blast 15L
Novak DjokovicBabolat VS 16Luxilon ALU Power 16L

Final Thoughts

I know I sound a bit like a broken record here, but there really is no right or wrong. Each player will have their own preference that suits their specific playstyle. With that in mind, see if you can try out a few different gauges and see which you prefer.

If you’re a beginner, a 16 gauge string will do fine. If you need more power, go up a gauge. If you want more durability, go down a notch. It’s not a race to find the best gauge right away, and players will frequently change their preferences as they adapt their style and new string technology is released.

Well, there it is folks. Hopefully, you’ve got a better understanding of how to choose a tennis string gauge. If you have any questions at all, please feel free to get in touch via the comment section below.

Thanks for stopping by.  

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