Quick answer: the two numbers are main strings (vertical) by cross strings (horizontal). Fewer strings — an "open" pattern like 16×19 — move more on contact, generating more spin and a softer feel. More strings — a "dense" pattern like 18×20 — move less, giving more control and durability but less spin.
What the numbers actually mean
A 16×19 pattern has 16 main strings running head-to-handle and 19 cross strings running side-to-side. An 18×20 pattern packs in two extra mains and one extra cross, leaving less gap between strings.
Open patterns (16×18, 16×19)
- More spin: wider gaps let strings shift and snap back on contact, grabbing the ball longer and imparting more topspin — the main reason open patterns dominate the modern spin-heavy game.
- Softer feel: more string movement absorbs some shock, giving a plusher, more comfortable sensation on contact.
- Less durable: with fewer strings sharing the load, each string wears faster — expect to restring more often, especially with polyester.
Dense patterns (18×20)
- More control: less string movement means a more predictable, "what you see is what you get" response — the ball goes where the racket face points with less variance.
- More durable: load is spread across more strings, so each one lasts longer before notching or breaking.
- Less spin, firmer feel: the trade-off for that control and durability is a flatter, crisper contact with noticeably less spin potential than an open pattern strung identically.
The middle ground: 16×20
A useful hybrid found on many all-round frames — the 16 mains keep spin potential reasonably high while the extra cross string adds a touch more control and durability than a full 16×19.
Pattern matters as much as string choice
A spin-friendly polyester strung into a dense 18×20 frame will always produce less spin than the same string in an open 16×19 — the physical pattern sets the ceiling, and string choice fine-tunes within it. If you are chasing spin, check the pattern before you check the string.
Matching pattern to your game
- Heavy topspin, modern baseline game: 16×19 — maximum spin and a comfortable, forgiving feel.
- Flat, precise ball-striking, frequent string breakers: 18×20 — control and durability first.
- Not sure yet: 16×20 — a sensible all-round starting point.
Our recommendation
String pattern is fixed to the frame, so it is one of the first things to consider when choosing a racket — not something to fix afterwards. If you already own a racket and want more spin without switching frames, dropping tension slightly and choosing a spin-friendly polyester is the next best thing.