Tennis String Gauge Explained: Does String Thickness Actually Matter?
Updated: Oct 14
Your teammate's strings last a month and yours snap in a week, even though you both play the same string. Check the pack: the small number after the name, the gauge, may be the reason.
Here is tennis string gauge explained in one line: the higher the gauge number, the thinner the string. Thinner strings tend to give a little more feel and bite but break sooner, and thicker strings tend to last longer and feel firmer. So does gauge matter? Yes, but in our experience less than most players think. String material and tension usually change how a racket plays far more than gauge does.
What does tennis string gauge mean?
Gauge is a thickness label. A higher number means a thinner string, and an "L" (for "light") means a half step thinner than the number in front of it. So 16L sits between 16 and 17.
The gauges you will see most often, thickest to thinnest, with typical diameters from Tennis Warehouse's gauge chart at the time of writing:
15L: about 1.35 mm.
16: about 1.30 mm, a popular middle of the road choice in our experience.
16L: about 1.22 to 1.28 mm.
17: about 1.20 to 1.25 mm.
18: about 1.15 to 1.20 mm.
Here is the catch: brands do not use the same cutoffs. A 1.25 mm string is sold as 16L for Luxilon ALU Power and as 17 for Babolat RPM Blast, according to Tennis Warehouse listings at the time of writing. That is why we read the millimeter number on the pack, not just the gauge.
Does a thinner tennis string give more spin?
A little, for some players. Many stringers and string testers report that thinner strings bite into the ball slightly more and snap back a bit more easily, which can help spin and feel. But your swing does most of the work: racket head speed and a low to high path matter far more than a small change in gauge. Dropping from 16 to 17 will not turn a flat hitter into a topspin player.
What a thinner string does more reliably is wear through sooner, because there is less material at each crossing for the strings to saw through.
Does string gauge affect durability?
This is where gauge matters most. A thicker string has more material, so it generally lasts longer before it breaks. If you break strings every couple of weeks, moving up to 16 or 15L is one of the simplest fixes, often paired with a more durable string type. Raising your tension will not fix breakage; higher tension usually makes strings break sooner.
If you never break strings, the logic flips. A thinner gauge can give you more feel with little downside, because your strings will lose tension and go dead long before they wear through. That is especially true of polyester, which often goes dead well before it breaks. Our guide on how often to restring a tennis racket explains how to tell.
What gauge should I use?
Here is the starting point we use at our stringing bench in Eastvale:
You break strings often: try 16 or 15L, in a durable polyester or a hybrid.
You rarely or never break strings: try 17 for a bit more feel.
You are not sure: 16 is a safe middle.
Your arm gets sore: focus on string material and tension first. In our experience a soft multifilament or natural gut at a lower tension does more for comfort than any gauge change. See our post on the best tennis strings for tennis elbow.
For context, Tennisnerd's 2026 review of ATP top 50 setups found 1.25 mm was the most common diameter among the setups it had data for. Top pros typically get fresh strings for every match, though, so breakage costs them nothing. It may cost you.
Our rule of thumb, and the one thing to tell a teammate: material picks the string, tension sets the feel, and gauge is the fine tuning knob, not the main dial.
Example: how we choose a gauge at A1 Stringing
Say a varsity player from Eastvale or Corona brings in a racket strung with a 17 gauge polyester and keeps breaking it before matches. We would usually suggest the same string in 16, or a hybrid with a softer cross, strung within the frame's recommended range. If you are new to polyester or still picking a tension, our guide to string tension for high school tennis players covers the tension side, and our string types guide covers materials.
Quick answers
Is 16 or 17 gauge better? Neither is better for everyone. A 16 gauge string generally lasts longer and suits players who break strings, while 17 gives a bit more feel and suits players who rarely break strings.
What does the L in 16L mean? L stands for light. It marks a half step thinner than the number, so 16L is thinner than 16 and thicker than 17.
Should I change gauge and tension at the same time? We recommend changing one thing at a time. If you switch gauge and tension together, you cannot tell which change made the difference.
How A1 Stringing can help
Not sure which gauge fits your game? Tell us your racket, how often you play, and how often you break strings, and we will recommend a string, gauge, and tension. We string premium strings only from Wilson, Luxilon, HEAD, Solinco, Babolat and Yonex, and every job includes a free overgrip.
Book a day ahead and your racket is strung while you wait. Need it today? Same day rush slots are available. Drop offs at the 24/7 drop box are ready in 24 to 48 hours. Pickup and drop off is also available in nearby zones around Eastvale, Corona and Chino Hills.
Current prices for every service, from stringing and rush slots to pickup, mobile visits and the 3 Pack, are always up to date on our Book Online page. Prices do not include sales tax.
Ready to dial in your setup? Book your restring online, or text (909) 334 2676.
Follow A1 Stringing on Instagram at @a1_stringing for stringing tips and shop updates, and share this post with a teammate who needs it. New posts go up every Thursday.
A note on this post: this is general information based on our experience as stringers and on the sources referenced above. It is not medical or professional advice, and the right string, tension, and equipment for you depend on your racket, technique, and physical condition, so results vary. Always check your racket manufacturer's recommended tension range, confirm current prices and specifications with the retailer or manufacturer, and see a qualified medical professional for any pain or injury.
Nathan Lee | Owner, A1 Stringing
Comments