Tennis String Gauge

Understanding Tennis String Gauge: How To Choose

There are a lot of options to choose from when it comes to getting a tennis string. But there are various attributes to consider, one of which is the tennis string gauge or thickness. So, why does string gauge matter? In order to understand which tennis string would be ideal for you, you need to know about tennis string gauge. 

While you may think tennis string gauge may seem like something you can overlook, it is not. It can influence your gameplay to a great extent. Keep reading to get a comprehensive understanding of tennis string gauge. 

Tennis String Gauge Sizes and Measurements

There is more than one measurement type for tennis string gauges; an international gauge, the string diameter measurement in millimeters, and the US gauge. The millimeter measurement and the US gauge is the most commonly used quantifier.  

International Gauges Measurements US Gauges
12 1.65 – 1.80 mm 13
11 1.50 – 1.65 mm 14
9.5 1.41 – 1.49 mm 15
9 1.33 – 1.41 mm 15L
8.5 1.26 – 1.34 mm 16
8 1.22 – 1.30 mm 16L
7.5 1.16 – 1.24 mm 17
7 1.06 – 1.16 mm 18
4 0.90 – 1.06 mm 19
3.5 0.80 – 0.90 mm 20
3 0.70 – 0.80 mm 21
2 0.60 – 0.70 mm 22


Gauges of a tennis string are typically marked on the string packaging. You can also read our top picks for the best tennis strings for your playing style and playability

What is a tennis string gauge?

What is a tennis string gauge

The thickness or diameter of a string is measured as the gauge. Different thicknesses of tennis strings are available on the market. Thicker gauge typically provides more control and durability. On the other hand, you will get more comfort and power from the thinner gauge. 

The gauge of tennis strings typically ranges between 1.05mm to 1.41mm. The most available tennis string gauge ranges from 1.20 to 1.30 mm. 

In Europe, a millimeter is widely used as a measurement, and string thickness is also referred by an entire number. In the USA, a lower number indicates a thicker gauge. On the other hand, the thicker gauge in Europe is indicated by the higher number.

That’s not it. It gets even more complicated when you will see “L” beside some gauges. The “L” means the string is thinner and it stands for “Light”. So, a string that has 15L written on it will be thinner than a 15-gauge string but will still be thicker than a 16. Similarly, compared to a 16, a 16L will be thinner but it will still be not as thin as a 17. The same goes for the rest of the measurements. 

The main difference between tennis string gauge 16 vs 17 is their thickness. 1.26 – 1.34mm is the diameter or thickness of the 16 gauge string, while the 17 gauge strings fall in the range of 1.16 – 1.24mm. 

This means the more durable option will be the 16 gauge string. However, if you want more feel, then the 17 gauge string is for you. 

If you choose thinner strings, the cost could outweigh the benefits as you might need to restring them frequently. 

If you want a string that provides more durability than 17 gauge but still gives you a better feel than 16 gauge, then you are looking for something that exists between these two – which is 16L.

The primary difference between a 16 vs 16L is that the latter is thinner than the former. The 16L is the half size and it is reported by the letter “L”, which is sort of “Light”.

While the diameter of a 16 gauge string would be around 1.30mm, a 16L would have around 1.26mm of diameter. 

The Effect of String Gauge on Performance

The difference between string gauges is not just in numbers. It would be futile to know tennis string gauge if you don’t understand how the thickness or diameter of the string impacts your performance. 

There are a number of factors that one needs to consider to select the ideal string gauge. They are as follows. 

String Gauge on Performance


When you are comparing gauges, remember, the thicker the gauge, the more long-lasting and durable the string will be.

During a tennis game, the strings generate friction at the cross-sections – where the strings overlap each other. Over time, the strings cut into each other. That’s when they start to notch. So, it goes without saying that a thicker gauge will be able to withstand this friction longer, thus, will last for a long time. 

However, keep in mind that there are other factors that can impact the longevity of a string, which include, construction, material, the density of string pattern, and tension. 

All things considered, if you want durability, then thicker strings are the better choice. 


Another aspect where the difference in tennis string gauge can have an influence is the feel of the strings. Many players affirm that thinner strings provide a better feel. Typically, the string will be on the softer side, which will grab the ball and give the player a more connected feel. 

Spin Potential 

Spin generation is an important part of tennis. Players significantly rely on their string gauge to influence potential spin. Thinner strings are likely to be able to produce more spin, while a player will be able to generate less spin potential with thicker strings. 

The ball gets buried deeper in the thinner strings, which allows it to grab the ball and produce more potential spin. On the other hand, if the string is thicker, it will have less bite, thus, lower spin potential. 

Nonetheless, only having a thin string gauge doesn’t guarantee the automatic generation of spin. It is an important factor among many that can influence spin. Your racquet head speed, grip, and technique will have the most vital impact on the spin. 


The same type of thinner strings are more elastic and can pocket the ball better. Therefore, they can help you generate more power. 

In summary 

Thicker strings:

Thinner strings: 

How does the string gauge affect playability?

String gauge affects playability to a great extent. A string gauge can influence the power, spin, and control of your shots. That’s not all. It also determines how durable, and comfortable your racquet will be and how much feel you will have during play. 

A higher gauge string can improve your playability as it can help you produce more power and spin. They are also more comfortable to play with. However, they lose tension faster and tend to break more frequently than thicker strings. This is because the generated friction during the play can cut through thinner strings faster. 

On the other side of the spectrum, you have the thicker string or the lower gauge string. Because of their thickness, frictions are not able to cut through them as faster as they can on thinner strings. This makes them more durable. 

However, durability comes with a cost, which is less power and less spin. Plus, they are also less comfortable to play with. Nonetheless, lower gauge strings are a better choice for the players who break their strings often.  

string gauge affect playability

So, how the gauge affects your playability is quite simple to understand. If you want to have more playability, go with the higher gauge strings and if you want to have durability, a lower gauge string is your best bet. 

However, there is another factor that influences your playability greatly, which is the material of the string. While string gauge is a vital factor, the material the strings are made from is also equally, if not more, important.

So, if you want to have the best strings for power, a multifilament or natural gut string would be your better choice. Alternatively, if you are a pro looking to produce more spin and have more control, then a polyester string would be the ideal choice for you.

Difference between thinner gauge string vs thicker gauge strings

Thicker strings mean more durable strings. However, if you are not a regular string breaker, you don’t require 1.30 mm or above. While a thinner gauge gives you more comfort, a better feel, and a grab on the ball, a thicker gauge gives more control and is more durable.

When you hit the ball, the strings move and generate friction. Because of this friction, over time, your strings will slash each other and break eventually. 

Compared to the lower gauge or thicker strings, the higher gauge or thinner strings tend to move more. This result in more friction, which causes them to break more quickly. 

And since, a thinner string has less diameter than the thicker one, there is actually less material to cut through. In simple words, the thinner strings break quicker than thicker strings. 

Besides just moving around more in the string bed, higher gauge strings also create a better trampoline effect and are more flexible as well.

High gauge or thinner strings will help you produce more spin and power but will break quicker compared to a thicker gauge string. 

On the other hand, the thicker gauge will be less capable of providing power, spin, and feel, but will maintain tension longer and be more durable. 

However, there is another factor that influences your playability greatly, which is the material of the string. While string gauge is a vital factor, the material the strings are made from is also equally, if not more, important. 

So, if you want to have the best strings for power, a multifilament or natural gut string would be your better choice. Alternatively, if you are a pro looking to produce more spin and have more control, then a polyester string would be the ideal choice for you.

string gauge guide

Popular Gauges and Examples

There are 9 different varieties of tennis string gauges. They range from 13 to 22. And lower gauge means thicker strings, while a higher gauge means thinner strings. 

You may have noticed that the gauge printed on your tennis string packet is often accompanied by a number. This number refers to the diameter of the string and the gauge itself characterizes the string classification range. 

For example, 16 gauge strings represent strings between 1.26 to 1.30mm in diameter. 

You can also find a thinner version of some string gauges. This means there is a bit of difference between a standard string of a gauge and the actual string thickness. 

String gauges that are most popular tend to range from 15 to 18. But, below you will find a list of all the available U.S string gauges. 

Here are a few examples of popular strings along with the available gauges:

String Gauges
Wilson NXT 16, 17
Luxilon ALU Power 15, 16L
Prince Synthetic Gut 15L, 16, 17
Babolat VS Touch 15L, 16, 17
Tecnifibre X-One Biphase 15L, 16, 17, 18

Let’s look at the example of a couple of strings with the string comparison tool.

Babolat RPM Blast 1.30 vs 1.20

Strings Gauge Comparison

Most of the factors are similar between both of the gauges, as you can see from the comparison table. However, the thinner gauge has more spin potential but significantly less stiffness. Stiffer string tends to have higher tension loss, so that is not that big of an issue. Nonetheless, it is quite understandable what you will get if you go with thinner gauge string such as the Babolat RPM Blast.

What Gauge String Do Tennis Pros Use with Cart

The gauges used by the pros are obviously some of the best. However, your decision shouldn’t solely depend on it. Because, for the pros, budget is not an issue. So, their ideal choice might be illogical for you.

That being said, here is a list of some of the best professional tennis players and the tennis string gauge they use.

Player Mains Crosses
Roger Federer Babolat VS 16 Luxilon ALU Rough 16L
Rafael Nadal Babolat RPM Blast 15L Same
Novak Djokovic Babolat VS 16 Luxilon ALU Power 16L
Daniil Medvedev Tecnifibre ATP Razor Code 17 Same
Dominic Thiem Babolat RPM Power 17 Same
Serena Williams Wilson Natural Gut 16 Luxilon 4G 16L
Naomi Osaka Yonex Poly Tour Strike 16L Same

Which String Gauge Should You Use?

Your personal preferences should be your first consideration while deciding on which string gauge you should use. That said, a 16 gauge string would be the ideal option if you are starting out. It is sort of in the middle of the string gauge spectrum, so you can hope to get a good balance of durability as well as performance.

And as you progress as a tennis player, you will likely be able to determine whether thicker or thinner string will be better for you. When starting, your ideal tennis string choice should be the one that has multiple gauges available.

People who do not play tennis frequently or club players tend to choose thicker strings because of their durability. And the thinner string is preferred by high-performance players as feel and comfort are their priorities.


16 or 17-gauge strings are in the middle of the gauge spectrum. They are not the thickest choice nor they are the thinnest choice. 16 gauge is a bit thicker than the 17 gauge.

A 16 gauge string would be the best gauge for beginners. Since it is on the middle ground, it offers a combination of performance and durability, which will be great for someone who is starting out. 

Tennis string gauge is not one size fits all. The best gauge for someone depends on various factors.

Final Thoughts

Having the right tennis string gauge can really have a positive impact on your game. Hopefully, this article was able to help you comprehend the tennis string gauge. Besides the tennis string gauge, also consider choosing the right material. And remember, a higher gauge string will improve playability but will break frequently, while a lower gauge won’t break so often, but you will have to play with less spin and power. So, consider what you want from your tennis string.

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