Tennis String Gauge Guide:
16 vs 17 vs 18 Explained
String gauge — the thickness of your string — has a measurable impact on spin, power, durability, and arm comfort. Yet most players never think about it. This guide explains exactly how gauge affects your game and which thickness is right for your playing style.
What Is String Gauge?
String gauge refers to the diameter (thickness) of the string. Confusingly, a higher gauge number means a thinner string — 18g is thinner than 16g. Strings are also commonly listed in millimetres, which removes the ambiguity: 1.30mm is thicker than 1.20mm.
The common gauges you'll encounter in tennis strings:
How Gauge Affects Your Game
| Property | Thicker (16g) | Thinner (17–18g) |
|---|---|---|
| Spin | Moderate | Higher — bites into ball more |
| Feel | Moderate | More nuanced, elastic response |
| Power | Slightly less | Marginally more — more string deflection |
| Durability | Longer-lasting | Breaks faster, especially for hard hitters |
| Arm comfort | Moderate | Slightly better — more elastic = less shock |
| Control | Slightly more consistent | Can feel less predictable for beginners |
The differences between adjacent gauges (e.g. 16g vs 17g) are real but not dramatic. They become more noticeable over time — thinner string loses tension faster, so a 17g set that felt great at first may feel noticeably different after 10 hours of play.
16g (1.30mm): The All-Rounder
16g is the most popular gauge for a reason: it works well for almost everyone. It's durable enough for regular club play, provides a comfortable feel across all string types, and doesn't require frequent restringing. The vast majority of club players play their best tennis on 16g strings.
Luxilon ALU Power 16 (1.30mm)
The classic ALU Power in the standard 16g gauge. Slightly more durable than the 16L version with a similar feel profile. Excellent for club players who want the ALU Power experience with better longevity.
17g (1.25mm): More Spin and Feel
17g is the choice of spin-focused players and those who want a more elastic, responsive string bed. The thinner profile bites into the ball more on topspin strokes and gives a livelier feel on volleys and touch shots. The trade-off is reduced durability — expect to restring more often.
16L (1.28mm) is a popular compromise — slightly thinner than 16g for more spin and feel, while maintaining better durability than 17g. Luxilon ALU Power 125 is the world's most used professional string and comes in this size.
Luxilon ALU Power 125 (16L)
The most used professional string in the world. The 16L gauge hits the sweet spot between 16g durability and 17g feel. Exceptional control, predictable response, and the distinctive ALU crisp feel that advanced players love.
18g (1.20mm): Maximum Bite
18g is the thinnest gauge commonly available and is used primarily by two types of players: advanced spin machines who restring every few sessions, and players using natural gut where 18g delivers exceptional feel without breaking as fast as synthetic strings.
Most recreational players should avoid 18g polyester — the durability hit is severe and the feel advantage is subtle. Consider 18g natural gut or multifilament if you want the thinner gauge feel without snapping strings every week.
Which Gauge Should You Choose?
Start with 16g if:
You break strings less than once per month · You play 1–3 times per week · You're a beginner or intermediate player · You prioritise durability and consistency over maximum spin.
Move to 17g / 16L if:
You play 3+ times per week · You're an intermediate–advanced player focused on spin · You're comfortable restringing more frequently · You use polyester and want a livelier feel.
Consider 18g if:
You're an advanced player with controlled swing and break strings rarely · You're using natural gut or multifilament · You want maximum bite and feel and can accept frequent restringing.
Gauge Recommendations by Player Type
Stick with 16g Synthetic Gut or Multifilament
Durability matters most at this stage. A 16g synthetic gut or multifilament gives you consistent performance and lasts long between restrings while you develop technique.
Shop at Racquet Depot16L / 17g Polyester
The sweet spot for developing spin players. A 16L shaped polyester like Solinco Hyper-G or Babolat RPM Blast gives you serious bite without snapping every few sessions.
Shop at Racquet Depot17g Multifilament
Thinner multifilament (17g) maximises the elastic, shock-absorbing benefits. Wilson NXT 17 or Tecnifibre NRG2 17 are excellent choices for players managing arm pain.
Shop at Racquet DepotGet a String Matched to Your Game
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Find my strings →Frequently Asked Questions
What gauge tennis string should I use?
Most club players do best with 16g (1.30mm) as it balances durability and playability. String-breakers should go thicker. Players focused on spin can go thinner (17g or 16L). Players with arm issues should use the thinnest gauge they can without snapping too often.
Does thinner string give more spin?
Yes. Thinner strings bite into the ball more on brushing strokes, generating more spin. This is why advanced spin players often choose 17g or 18g strings. However, the durability trade-off is significant — thinner strings break much faster, especially for hard hitters.
What does 16L mean in tennis string gauge?
The L stands for 'light', meaning it falls between two standard gauges. 16L (also written 1.25mm) sits between 16g (1.30mm) and 17g (1.25mm). It offers slightly more bite and feel than 16g while being more durable than 17g. Many popular strings like Luxilon ALU Power come in 16L.
Do professionals use thinner or thicker strings?
Most ATP professionals use 16L (1.25mm) polyester strings. This gauge gives them the spin and feel benefits of going thinner without sacrificing too much durability. Pros restring every match so durability matters less to them — recreational players should weight durability more heavily.
Does gauge affect tension?
Thinner strings may require slightly lower tension to achieve the same feel as thicker strings. As a general rule, if you switch from 16g to 17g, consider dropping 1–2 lbs of tension to maintain a similar string bed feel.