Tennis String Gauges Explained

Picking the perfect tennis string alone, can be a difficult task!

With so many different string types out there, not to mention different manufactures and playing characteristics, cutting through the noise to find the right string for your game can require a lot of research.

One of the most commonly overlooked elements of choosing the right string for you is the thickness or ‘gauge’ of the string.

You may not even know you could get a different string thickness!

But, in reality there are a wide range of different string gauges that can alter the playing characteristics of a string dramatically.

So, understanding the different string gauges is certainly an important part of picking the perfect string for you!


The Different Types of Tennis Strings


Polyester Strings


One of the more popular and inexpensive options for stringing your racket is using a polyester string.

These tend to be a bit stiffer and more hardwearing than any other type of string, so are ideal for players that hit with a lot of power but are looking to control the ball.

Due to their stiff nature, they don’t tend to offer much in the way of power, but are ideal for big hitters who are looking to add more spin and control to their game.


Natural Gut Strings


Generally the more expensive option when it comes to tennis strings, natural gut is made from Bovine intestines and is the perfect option for someone looking to generate as much power as possible.

Natural gut strings tend to be very flexible and therefore offer the most power and comfort of any string type, as they produce a ‘trampoline’ like effect on the ball.

These strings tend to hold their tension the best, whilst offering the most natural and plush feel of any string. So, why not just pick natural gut every time?

Because they are not particularly durable so need to be replaced regularly, and quite expensive! This makes them quite unaffordable for most recreational players.

However, if you are after an extremely comfortable and forgiving string, natural gut is definitely the way to go.

A top tip is to combine a natural gut with a multifilament or polyester string to increase its durability, whilst still retaining that plush feel!


Multifilament Strings 


Multifilament strings are comprised of hundreds of tiny fibres that play in a similar way to natural gut strings.

Often much cheaper than natural gut, multifilament strings still offer a good level of playability and softness, so are a good alternative if you are looking to save some money!

What are the Different String Gauges


Tennis string gauges come in 9 different varieties, from gauge 13 to gauge 22. Although this may sound confusing, the lower the gauge number, the thicker the string!

Now, the gauge that is printed on the packet of your tennis strings is often accompanied by a corresponding number.

This number is the diameter of the string itself, whereas the gauge represents the range of that string classification.

So for example, a gauge 16 represents strings between 1.26mm and 1.30mm in diameter.

Some manufacturers offer lighter or thinner versions of certain string gauges too.

This means there is a slight difference between the actual string thickness compared to a standard string of that gauge.

However, most tennis string manufacturers across the board are starting to standardize their string gauges to make it easier for customers to pick the right string for them.

The most popular string gauges tend to fall between 15 and 18, but we have included a list of all the available string gauges below (U.S. gauges):


  • Gauge 13: 1.65 – 1.80mm
  • Gauge 14: 1.50 – 1.65mm
  • Gauge 15: 1.41 – 1.49mm
  • Gauge 15L: 1.33 – 1.41mm
  • Gauge 16: 1.25 – 1.34mm
  • Gauge 16L: 1.22 – 1.30mm
  • Gauge 17: 1.16 – 1.24mm
  • Gauge 18: 1.06 – 1.16mm
  • Gauge 19: 0.90 – 1.06mm
  • Gauge 20: 0.80 – 0.90mm
  • Gauge 21: 0.70 – 0.80mm
  • Gauge 22: 0.60 – 0.70mm.

What’s the Difference? 


Ultimately, when it comes to gauges the main thing to consider is playability versus durability.

This means that the thicker the string, or lower the gauge, the more durable it will generally be.

Whereas, playing with a higher gauge, or thinner string, will result in strings breaking more frequently.

Why does this happen?

Well, when you hit the tennis ball, your strings move and create friction.

The more friction that is created over time, the quicker your strings will notch and eventually break.

When using thinner, higher gauge strings, they tend to move more in the string bed than thicker, lower gauge strings.

This means they rub together more and create more friction, making them break more quickly.

Couple this with the fact that of course a thinner string has a smaller diameter to begin with, so less material to actually wear through, and all other things being equal, a thinner string will break  more quickly than a thicker string.

Moreover, a higher gauge string tends to offer more spin and power on the ball than a lower gauge string.

This is because a higher gauge string will not only move around more in the string bed, but also be more flexible and create a greater ‘trampoline’ effect than a lower gauge string.

So, we have a clear trade off here. Thinner, high gauge strings tend to produce more power and more spin, but break a lot quicker than thicker, low gauge strings…

Now, we also need to factor in the type of string you are playing with at this point.

Because, although string gauge is an important factor, it does not override the actual material the strings are made from.

This should be your primary focus when choosing a tennis string.

So if you are looking for the best strings for power, you would be best off going for a natural gut or multifilament string.

Whereas, if you are an advanced player looking for more control and spin when hitting the ball, then you may be better off starting with a polyester string.

Which You Should Choose


Once you have decided which of the string material types is best for you, you can decide on your string gauge.

This really comes down to how important feeling is to you, your budget and how often you play tennis.

If you are looking for the ultimate feel and comfort from your strings, are only playing a couple of times per month and don’t mind getting your racket strung with an expensive string, then going for a high gauge natural gut string would be the best fit for you.

This will give you the most plush, soft feel possible.

However, if you are at the other end of the spectrum and looking for a hard, stiff string that will not break easily and you play daily, you may be better off going for a lower gauge polyester string.

This would not be as friendly on your arm or provide a particularly precise feel, but if you are looking to keep your costs down and are a heavy hitter trying to control your natural power, then this would be a good option for you.

Finally, if you are new to the game and not too sure which string gauge to go for, then gauge 16 or so is a great place to start.

Almost all commonly stocked tennis strings come in gauge 16 as it sits almost exactly in the middle of the string gauge range.

This also gives you plenty of room to move a couple of gauges up or down depending on your needs.



Ultimately, tennis string gauges are an important thing to understand if you are looking to fine tune your equipment setup on the court.

Picking the right tennis string material, tension and gauge are all important factors to consider.

Remember, the thinner the string (higher gauge), the more playable it will be, but it will break far more often and probably cost you more money.

Whereas, a thicker string (low gauge) will break far less often, but you will give up some power and spin in the process.

So consider how often you will be playing, what you need your strings to provide to your game, along with your budget and playing preferences.

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