Tennis String Gauge and Its Impact on Performance

Tennis String Gauge

and its impact on performance

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When it comes to tennis string, one of the key attributes to understand is gauge or the string’s thickness and how it impacts performance.

While it’s a simple concept, many players overlook string gauge and therefore don’t fully reap the benefits of stringing their racquet with the best gauge for their level and style of play.

In this guide, we’ll explain the meaning behind string gauge, review the variety available to players, and help you identify what string gauge to use along with a handful of our favorite picks.

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What is Tennis String Gauge?

Gauge is a measure of a string’s diameter or thickness, which according to industry standards, falls between 0.60 and 1.80 millimeters.

String gauge is a personal preference with various advantages and disadvantages on both ends of the spectrum.

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String Gauge Sizes and Measurements

Since tennis string gauge is the thickness of a string, we can measure its diameter to come up with its size.

The following chart outlines the types of string gauge or measurements currently available.

US GaguesInt. GaugesMeasurements
13121.65 – 1.80 mm
14111.50 – 1.65 mm
159.51.41 – 1.49 mm
15L91.33 – 1.41 mm
168.51.26 – 1.34 mm
16L81.22 – 1.30 mm
177.51.16 – 1.24 mm
1871.06 – 1.16 mm
1940.90 – 1.06 mm
203.50.80 – 0.90 mm
2130.70 – 0.80 mm
222.50.60 – 0.70 mm

Depending on where you live, you may see the measurements represented in two different ways on the packaging.

In the United States, string gauge measurements can be confusing because the number representing the gauge is counterintuitive. As you can see from the table above, the higher the gauge, the thinner the string, and the lower the gauge, the thicker the string. The “L” you see displayed next to some of the gauges refers to “light.”

The international measurements are the opposite with higher gauge representing thicker strings and vice versa.

However, regardless of where you live, you’ll typically find string gauge represented in millimeters (mm), or in some cases, that’s all you’ll find. With that in mind, players in the US will find it helpful to familiarize themselves with these measurements.

The most common measurements, and therefore widest selection of strings that you’ll find available, are 17, 16L, and 16. While there are strings available outside this range, most players tend to fall within this range when stringing their racquets across many different types of string.

For context, here’s a selection of five popular strings and available gauges that you can purchase.

Wilson NXT16, 17
Luxilon ALU Power15, 16L
Prince Synthetic Gut15L, 16, 17
Babolat VS Touch15L, 16, 17
Tecnifibre X-One Biphase15L, 16, 17, 18

If you’re looking for a few of our other favorite picks, check out our guide to the best tennis strings in 2020.

Helpful tip: It’s important to note that the above measurements are guidelines, which most manufacturers follow. However, from time to time, you may come across string sets that fall outside of these recommendations, so check the package to know what you’re using.

String Gauge and Performance

Of course, knowing string gauge isn’t all that helpful if you’re not clear on how the thickness of a string impacts performance.

There are three main factors players usually consider when selecting a string gauge: durability, spin potential, and feel.


When comparing different gauges for the same string, the heavier the gauge or thicker the string will be more durable and long-lasting.

When you play tennis, your strings produce friction at the cross-sections where they overlap each other. Over time you’ll notice that your strings cut into each other and begin to notch, so naturally, the thicker they are, the longer they’ll last. Thicker strings can also withstand greater impact, which helps extend the life, too.

However, when it comes to durability, keep in mind that there is a wide variety of factors that can influence the longevity of a string, including material, construction, tension, and a string pattern’s density.

All else equal, thicker strings are more durable, and it’s a great rule of thumb to use when evaluating strings.

Spin Potential

Beyond durability, players also rely on their string gauge to influence their potential for generating spin. The thinner the string, the more potential for spin, while the thicker the string, the less spin potential.

Thinner strings bury themselves deeper into the ball, and as a result, “grab” the ball, which results in more spin. A thicker string has less bite, resulting in a lower potential for spin.

However, just because you have thin strings doesn’t mean you’re automatically going to generate massive spin. It’s one of many factors that can influence spin. However, your grip, technique, and racquet head speed will have the most significant influence over spin.


Another area where you’ll notice changes with different gauge is the feel of the strings. A thinner string will tend to offer more feel and connectedness with the ball as you’re hitting, which in turn can help players hit with better touch or finesse.

Which String Gauge Should You Use?

Every player’s needs and preferences are different. With this in mind, there are a variety of factors you can keep in mind when evaluating strings and determining which is best for you.

Types of String

The type of string your using frequently has an impact on the gauge that you choose. Here’s a brief look at the different types of strings:

  • Natural Gut: high power, comfort, tension mantience, exceptional feel, prone to breakage, and susceptible to moisture
  • Synthetic Gut: mid-range tennis strings offering well-rounded performance across the board, typically lack durability
  • Multifilament: the synthetic alternative to natural gut, these strings offer power, comfort, and hold their tension well
  • Polyester: low powered spin-friendly strings that are stiff and durable, but tend to lose their tension quicker than other strings
  • Kevlar: the most durable strings that maintain their tension well

As you read the descriptions, it might begin to click why you might consider a higher or lower gauge for each.

As an example, you might string with a lower gauge (thicker) tennis string if you’re using synthetic or natural gut to help increase the durability or life of your strings. Whereas, if you’re using polyester strings, you may opt for a higher gauge (thinner) option to help maximize spin.


If you can’t afford to string your racquet frequently, I’d also recommend you string with a thicker low gauge string to help avoid breakage and increase the longevity of your strings.

Racquet stringing can be expensive, especially when you take into consideration the labor to string your racquet. You can go thicker, but 16 will usually do the trick while helping maintain solid playability and potential for spin.

If you want to play with a thinner gauge, but budget is a concern, you may want to consider the use of string savers to get the benefit of a higher gauge without breaking the bank.

Frequency of Play

Another factor to consider is your frequency of play. If you’re playing only twice a month, then you might not be as concerned with longevity, so you may be comfortable stringing with a higher gauge.

After all, you’ll still want to replace your strings on a semi-regular basis since strings naturally lose their tension and liveliness over time.

On the other hand, if you’re playing five days a week and you can’t afford to restring every week, then you might want to use a lower gauge to increase the life of your strings.

Level of Play

If you’re learning how to play tennis, then I’d recommend you start with a thicker inexpensive string like synthetic gut.

When you’re just getting started, you’ll unlikely be able to notice the subtle differences between a higher or lower gauge string. However, you will be more likely to appreciate the extra durability of a lower gauge string that doesn’t break easily and limits your restringing frequency.

As a result, for beginners, I’d recommend 16 gauge (1.26 to1.34 mm) to start. Over time as your skills develop, you’ll find your appreciation for strings do too.

If you’re intermediate to advanced, then I’d recommend you experiment with different gauges to get a feel for the change in performance. There’s no right or wrong answer – instead, keep the pros and cons in mind, and let your preferences drive your decision making.

Style of Play

Once you cross over to an intermediate level of play, you’ll begin to develop a style. Examples of different styles include Rafael Nadal’s aggressive baseline play or Roger Federer’s all-court fineness play.

In the case of Nadal, he hits with an incredible amount of topspin and uses a 15 gauge polyester tennis string from Babolat called RPM Blast.

Federer, on the other hand, doesn’t hit with as much topspin, but has an impressive arsenal of shots and regularly plays from all areas of the court. He strings a hybrid setup with 16 gauge natural gut in the mains and 17 gauge polyester in the crosses, which brings us to our next point.

Hybrid Stringing

There aren’t rules when it comes to hybrid stringing, where one type of string is used for the mains and another for the crosses.

However, it’s common for players to use a different gauge for each based on the characteristics the strings offer, as Federer does.


When it comes to gauge and stringbed stiffness, which impacts comfort, studies have been inconclusive. In other words, different strings will offer more comfort at higher or lower gauges.

With that said, you’ll have to be the judge when you find a string you like and experiment with different gauges. However, if you’re after comfort, the type of string you’re using, and the tension you’re stringing have a material impact that is worthy of consideration.

How Do You Know What You’re Buying?

String manufacturers always label their strings with the gauge or measurement in millimeters. Here are a few examples of string packages with the gauge of the string highlighted.

Where to See String Gauge on the Package

Sometimes you’ll see the millimeters expressed as a whole number, i.e., instead of 1.30, you’ll see it shown as 130, as you’ll find with many Babolat string packages.

What the Pros Use

The gauge the pros use can be a useful point of reference, but don’t let it completely drive your decision making.

As an example, budget is not a concern when it comes to the top players, so what works for them might not make sense for you.

With that said, here’s a handful of pros and the gauge they use.

R. FedererBabolat VS 16Luxilon ALU Rough 16L
R. NadalBabolat RPM Blast 15LSame as mains
N. DjokovicBabolat VS 16Luxilon ALU Power 16L
S. WillaimsWilson Natural Gut 16Luxilon 4G 16L
N. OsakaYonez Poly Tour Strike 16LSame as mains
K. PlíškováBabolat VS 16Babolat Pro Hurricane Tour 17

String Gauge and Tension

A common question that comes up when talking about string gauge is what tension works best for a specific gauge string or how tension should be modified when moving up or down a gauge for the same string.

Unfortunately, there isn’t a perfect answer to either of these questions. That’s because some strings will string stiffer at high tension, while others at low tension.

As a result, my recommendation is to think about tensions effect independent of gauge when they make a change.

For example, if you’ve switched gauges and you find your clipping the net often, you might want to decrease your tension a few pounds. The result would be a less stiff stringbed, which produced a higher launch trajectory, i.e., more power, and should help.

If you’re stringing a racquet for the first time, we encourage you to consider the recommended tension ranges for the racquet and strings your using to help dictate a starting point for tension. We cover all these points in our resource on string tension, so be sure to check that out.

Wrapping up

Hopefully, this guide helps point you in the right direction, but don’t get too bogged down in the details. Starings aren’t permanent, so you’ll have plenty of opportunities to try something new.

As you progress, it can be helpful to experiment with different gauge tennis strings, especially within the same type of string, as performance will vary.

What gauge tennis strings are you using, and why? We’d love to hear in the comments below. Of course, if you have questions, drop us a note.

Home > GearStrings > Tennis String Gauge

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20 replies
    • TennisCompanion
      TennisCompanion says:

      Hi Bill,

      Great question. Yes, to a certain degree, tension does impact spin potential for polyester tennis strings. Polys have a unique attribute where they quickly snap back into place as you strike the ball. This snapback effect provides a small incremental improvement to your topspin, which is believed to increase slightly at lower tensions.

      You can read all about tension and spin potential here.

      All the best,

  1. Mike
    Mike says:

    I just demo raquet, liked it and purchased. Unfortunately strings on the demo were not available and a close substitute was provided. However , they are a 18 gauge. i do notice the diff from demo. I like the spin but after 4 separate 1 hour hits, my arm is killing me. Is it the strings?????
    thanks for all

    • TennisCompanion
      TennisCompanion says:

      Hi Mike,

      It’s more likely that the type of string would be the culprit than the thinner 18 gauge you’re using Can you share the name of the substitute string? Beyond the string, your racquet would have a substantial impact on shock and vibration and, therefore, comfort. Perhaps you can share the racquet you purchases too, and I can give you a full run-down on my thoughts.

      All the best,

    ARJAV SHARMA says:


    If you could kindly help me over this.

    I am hard hitter with heavy topspin. I am currently using a pair of Wilson Prostaff 100LS raqcuets with a 16×15 pattern. I play 6 days a week. With two hours every day.

    I have used Head Competetion2, Wilson Power strings but I end up breaking them every third day. I use a tension of 62-64 LBS which is 30-31Kgs.

    I wonder which strings should I use to avoid spending in heaps. Please recommend 5-6 Grades and their brands which I can find in India.

    On the contrary, at times I also use my older pair of Wilson Prostaff 5.0 Midplus, which has dense string pattern and I end up hitting with these two strings for more than 20 days on one racquet. With fabulous punch and topspin. Unfortunately due to heavier frame i cant use it now for a timely backhand.

    I am 33, kindly recommend me the best. I am also suffering from an elbow.

    Thanks a lot for your presence for us.


    • TennisCompanion
      TennisCompanion says:

      Hi Arjav,

      Thanks for sharing. From what I can gather, it sounds like you have two issues you’re experiencing.

      • Breaking strings too frequently (I’m sure the cost is adding up)
      • Suffering from some discomfort in your arm

      There are a few things I’d recommend you’d consider. First, between the two tennis racquets, I’d stick with your Wilson ProStaff 100LS, which features a lower stiffness rating of 63 (compared to 74 for the 5.0), and it’s lighter. It should help prevent a bit of discomfort you’re experiencing.

      I’d also consider alternative tennis strings. For now, I’m going to assume you want to stick with a hybrid string setup, so I’ll provide more durable options while keeping comfort in mind.

      As far as durability goes:

      • One option is to bump up the gauge of your multifilament NXT power. If you’re using 17 gauge, you can move up to 16, or you can even go up to 15 with NXT DuraMax.
      • Another option would be to consider a more durable multifilament – here are a few options: Tecnifibre X-One Biphase, Tecnifibre NRG2, or Babolat Addiction. You should find all of these last longer than NXT power at 16 gauge.
      • You can also string your polyester as the mains, which should help with the durability. However, the mains will primarily dictate the overall feel, which you may find results in a bit less comfort.

      With regards to comfort, you might consider switching up your polyester string too. Polyesters aren’t known for their comfort, but some deliver more than others. A few to check out include Head Sonic Pro Edge, Tourna Big Hitter Black 7, and Dunlop Black Widow.

      I made some assumptions in those recommendations based on what you shared. If there’s anything you want to clear up so I can provide a bit more info, please let me know.

      Lastly, I hope these strings are available in your area :) Unfortunately, I’m not as familiar with what you’re going to be able to find in India. Good luck in your search!

      All the best,

  3. William
    William says:

    Question: if I use a multifilament string (Tecnifibre MultiFeel) and I string 16g at 52lbs. At what tension would I string 17g string… to have the same sort of feel as the 16g… tighter or looser… and how many lbs difference…? Thanks.

    • TennisCompanion
      TennisCompanion says:

      Hi William,

      Unfortunately, what you’d be trying to mimic (stiffness of the stringbed) differs from string to string. That is, some strings are stiffer at thinner gauges, while others at lower gauges.

      Because of this, combined with the fact that a thinner gauge will inherently feel different makes this question tricky to answer without taking measurements for this string at varying tensions.

      With that said, you’ll need to test it out. My recommendation would be to start by stringing the 17 gauge 2-3 pounds tighter. If that works, you’re golden. If not, you’ll have to try 2-3 pounds looser and see how it feels. Ultimately, you won’t end up with the same feel, perhaps just similar.

      I wish I could give a more direct answer, but hopefully, this helps point you in the right direction.

      All the best,

  4. Robert
    Robert says:

    I just started playing with 17 gauge after many years of automatically using 16. My first time playing with the 17 gauge immediately I noticed better touch and feel on the ball, especially with drop shots. This said, I also noticed that ground strokes tended to go a little long, like an inch or so. I know my technique has something to do with this, but… I know there is a rule / guideline about stringing poly 10% lower than say multifilament. Is there also a rule / guideline when changing gauges. At 16 gauge I was stringing at 50lbs. At 17 gauge, I wish I had strung it at 52 or maybe more. Is there a rule / guideline when changing gauge by one level?

    • TennisCompanion
      TennisCompanion says:

      Hi Robert,

      Your question falls into a similar category as William’s above – it’s tricky to answer :)

      Ultimately, what you’d’ be trying to mimic is the stiffness of the stringed. However, some strings will string up stiffer at higher tensions while others will string up stiffer at lower tensions, which makes it difficult to put hard and fast rules in place for players when switching the gauge of their string.

      However, instead of focusing on tension as it relates to gauge, my recommendation would be to consider the effect of changing tension independent of gauge. In your case, you’re finding your shots are sailing slightly long.

      Based on what we know about tension, you’d want to bump it up 2-3 pounds to prevent hitting long. Higher tensions result in a stiffer stringbed, which decreases the launch angle of the ball resulting in less perceived power and more control.

      Good luck – would love to hear how things work out.

      All the best,

    • TennisCompanion
      TennisCompanion says:

      Hi Al,

      I wouldn’t worry too much about gauge when it comes to comfort and your tennis elbow. However, I would recommend a slightly lower tension, and more importantly, a softer multifilament tennis string if you’re not already using one.

      A few, I’d recommend:

      • Wilson NXT
      • Babolat Xcel
      • Tecnifibre NRG2
      • Tecnifibre X-One Biphase

      Good luck and I hope your tennis elbow gets better.

      All the best,


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