Quick answer: gauge measures string thickness, and the numbering is backwards from what you would expect — a bigger gauge number means a thinner string. 16 gauge is the thickest and most durable; 18 gauge is the thinnest, with the most feel and spin, but the shortest lifespan.
What the numbers mean in real terms
- 16 gauge (≈1.30–1.34mm): the thickest common string diameter — durable and long-lasting.
- 16L / 16.5 gauge (≈1.25–1.28mm): a popular middle ground between 16 and 17.
- 17 gauge (≈1.20–1.25mm): noticeably thinner, more feel and spin than 16, shorter lifespan.
- 18 gauge (≈1.10–1.16mm): the thinnest widely available gauge — maximum feel and spin, but wears through fastest.
Why thinner strings feel different
A thinner string embeds into the ball slightly more on contact and moves more freely against neighbouring strings, both of which increase spin potential and give a softer, more responsive feel. The trade-off is durability: less material means the string notches, frays and loses tension faster, especially against a topspin-heavy game or a partner's flat, hard hitting.
Why thicker strings last longer
More material per string means more is needed to wear through before it snaps or the tension collapses. Thicker strings also hold tension slightly longer, so play stays consistent for longer between restrings — useful for players who do not want to think about their string bed between visits.
Gauge and durability versus gauge and feel
There is no free lunch here: any gain in feel, spin or comfort from going thinner comes directly at the cost of durability, and vice versa. Players who break strings often, or who value consistency over feel, are usually better off a gauge thicker than players chasing maximum spin and touch.
Mixing gauges in a hybrid setup
Many players get the best of both by hybrid stringing — a thicker, more durable gauge in the mains (which take most of the wear) paired with a thinner gauge in the crosses (where feel matters most). This is a common way to stretch the lifespan of a spin-friendly setup without losing all of its feel.
Matching gauge to your game
- Frequent string breakers, beginners, value-focused players: 16 gauge — durability and consistent tension first.
- Most club players: 16L or 17 gauge — a sensible balance of feel and lifespan.
- Advanced players chasing spin and touch, who restring often anyway: 17 or 18 gauge.
Our recommendation
If you are not sure, start at 16L or 17 — it is the gauge most players settle on long-term. Go thinner only if you specifically want more spin and feel and are prepared to restring more often to get it.