String & Racket Finder
Tennis string gauge, explained
Gauge is simply the diameter of the string in millimetres. It is the smallest of the choices you make at the stringer, and the one most often oversold — but it is not nothing, and the direction of each effect is consistent.
Open the string bench →What thinner does
A thinner string bites into the ball more and moves more freely, so it generally produces a little more spin and a little more feel. It also stretches more, which reads as slightly more power and slightly more comfort. And it breaks sooner — that is the whole trade. A player who breaks strings every two sessions at 1.25 will break them faster at 1.20.
What thicker does
Thicker is more durable, holds tension marginally better, and feels more muted and more controlled. The cost is a little spin, a little feel, and a stiffer response. If you are going thicker purely to stop breaking strings, be aware you are also making the bed harsher — which matters if your arm is the reason you are reading this.
Where tension comes in
Tension moves things much further than gauge does. Lower tension gives more power, more comfort and a larger effective sweetspot; higher tension gives a more direct, more controlled, less forgiving bed. If you are trying to solve a problem, change tension first and gauge second — and change one at a time, or you will not know which did it.
Polyester is the exception worth knowing: it loses tension fast in the first hours and then keeps drifting, so a poly bed strung at the top of its range spends most of its life somewhere else entirely. That is why stringers often suggest poly a few pounds below what you would use with a multifilament.
What the market actually offers
Across the 358 beds here that state a gauge, the distribution is heavily concentrated — 1.25 mm is the default the industry has settled on, with 1.30 as the durability option.
| Gauge | Beds | Share |
|---|---|---|
| 1.16 mm | 2 | 0.6% |
| 1.18 mm | 4 | 1.3% |
| 1.19 mm | 1 | 0.3% |
| 1.20 mm | 31 | 10.0% |
| 1.22 mm | 4 | 1.3% |
| 1.23 mm | 19 | 6.1% |
| 1.24 mm | 18 | 5.8% |
| 1.25 mm | 147 | 47.3% |
| 1.26 mm | 1 | 0.3% |
| 1.27 mm | 10 | 3.2% |
| 1.28 mm | 5 | 1.6% |
| 1.29 mm | 1 | 0.3% |
| 1.30 mm | 67 | 21.5% |
| 1.32 mm | 1 | 0.3% |
Only four strings on the bench are listed in more than one gauge, so in practice the gauge decision is usually made for you by which string you pick.