How to Choose Tennis Strings: Tension, Gauge, and String Type

What Are the Main Types of Tennis String?

String type is where everything starts. Each category is built from different materials and constructed differently, which means they play, feel, and wear in distinct ways. Here's what separates them.

Polyester

Polyester (often called "poly" or "co-poly") is the most popular string among competitive and advanced players. It's a monofilament construction, meaning it's a single solid strand of material rather than a bundle of fibers. That makes it stiff, durable, and excellent at generating spin because the strings snap back aggressively after contact.

The trade-off is comfort. Poly is the firmest string type and sends more vibration into the arm. It also loses tension faster than other materials, which means the stringbed goes "dead" sooner, often before the strings actually break. For players who generate their own power through racquet head speed, poly offers outstanding control and spin access. For everyone else, a softer option usually makes more sense.

Popular picks: Babolat RPM Blast, Luxilon ALU Power, HEAD Lynx Tour, Solinco Hyper-G, Tecnifibre Razor Soft

Natural Gut

Natural gut is the original tennis string, and still the best-feeling option money can buy. It's made from beef intestine (serosa fibers), which gives it incredible elasticity, tension maintenance, and shock absorption that no synthetic string has been able to fully replicate. Gut returns energy to the ball efficiently and plays comfortably at a wide range of tensions, making it the most arm-friendly string on the market.

The downsides are price and moisture sensitivity. Natural gut costs significantly more than any synthetic and needs to be kept dry to perform its best. Many advanced and professional players use gut as a main string in hybrid setups to get the feel benefits without stringing a full bed.

Popular picks: Babolat VS Natural Gut, Wilson Natural Gut

Multifilament

Multifilament strings are the closest synthetic alternative to natural gut, and they're the string we recommend most often to players who aren't sure where to start. They're constructed from hundreds or thousands of tiny microfibers bonded together, which creates a plush, shock-absorbing stringbed. Multis are softer and more elastic than poly, and they produce a lively response with solid power.

The performance jump from synthetic gut to a quality multifilament is one of the most noticeable upgrades you can make to your racquet. You'll feel a more comfortable response at contact, better tension maintenance between restrings, and a livelier stringbed that returns more energy to the ball. For players dealing with arm issues, tennis elbow, or general discomfort after play, multifilament is the first recommendation. They wear faster than polyester, and the outer fibers will fray over time, but the core holds together until the string eventually snaps. Tension maintenance is better than poly but not quite as good as natural gut.

Popular picks: Wilson NXT, Tecnifibre X-One Biphase, HEAD Velocity MLT, Tecnifibre NRG2

Synthetic Gut

Synthetic gut (nylon-based) is the most budget-friendly option on the wall. It's a solid core wrapped in one or more outer layers, which gives it a balanced blend of feel, durability, and playability without excelling in any single category. Synthetic gut performs well across a wide range of racquets and tensions, and the price makes it easy to restring without thinking twice.

That said, if your budget allows, multifilament is a meaningful step up. Synthetic gut gets the job done, but it won't deliver the same comfort, liveliness, or tension stability that a good multi provides. Think of synthetic gut as the entry point and multifilament as the recommended starting line for players who want to feel a real difference in their stringbed.

Popular picks: HEAD Synthetic Gut, Babolat Syn Gut

Hybrid Setups

A hybrid setup uses two different strings: one in the mains (vertical) and one in the crosses (horizontal). The most common combination is polyester in the mains for spin and durability, paired with a softer string like natural gut or multifilament in the crosses for comfort and feel.

Hybrids let you split the difference between string types instead of committing fully to one. A poly/gut hybrid, for example, gives you significantly more spin than a full gut bed and considerably more comfort than a full poly bed. This is the setup most ATP and WTA pros use. The downside is added cost (two sets of strings or two individual packages) and slightly more complexity when communicating your preferences to your stringer.

Popular combos: Babolat RPM Blast mains + Babolat VS Gut crosses, Luxilon ALU Power mains + Wilson NXT crosses

String Type Comparison

What Tennis String Gauge Should You Use?

String gauge is the thickness of the string, measured in millimeters. Gauges range from 15 (thickest, around 1.35 mm) to 20 (thinnest, around 1.00 mm), with half sizes in between. The numbering runs backward from what most people expect: a lower gauge number means a thicker string.

That difference in diameter changes three things: durability, spin, and feel.

Thicker gauges (15, 15L, 16) resist notching and friction wear, so they last longer between restrings. The trade-off is a stiffer stringbed that can feel less responsive at contact.

Thinner gauges (17, 17L, 18, 19, 20) bite into the ball more aggressively for extra spin potential and produce a softer, livelier response. They wear out faster, though, especially for players who hit with heavy topspin or play frequently.

Gauge Reference Chart

What Tennis String Tension Should You Use?

Tension is the final piece. It controls the trade-off between power and control, and it's the cheapest variable to experiment with because your stringer can set it at any number within range.

The basic principle: lower tension creates a more elastic stringbed that generates more power and absorbs more shock. Higher tension produces a tighter, stiffer stringbed that gives you more control over ball placement, but you have to supply more of your own power.

Spin works a little differently than most players expect. Lower tension actually adds spin potential because the strings move and snap back more freely. High tension can make it harder to produce heavy topspin, even though it may feel crisper at contact.

Finding Your Recommended Range

Most racquets print a recommended tension range on the throat or inside the frame, usually somewhere between 45 and 70 lbs. That range is your sandbox. Stringing outside those bounds can stress the frame and void most warranties.

Where to start: The midpoint of your racquet's recommended range is a safe first step. For most frames, that lands around 54-58 lbs. From there, adjust based on how the setup feels during play.

Drop tension 2-3 lbs if your arm feels sore after play. The ball isn't clearing the net comfortably. You want more spin, and the strings feel too stiff to move.

Raise tension 2-3 lbs if you're overhitting and struggling to keep balls in the court. The racquet feels like it's doing too much on hard swings. You want a crisper touch on volleys and drop shots.

Tension by String Type

Different string materials respond to tension differently. The same tension number strung in poly versus natural gut will feel like two completely different setups.

How Do You Match Strings to Your Game?

By Level

Beginner: Start with a multifilament at your racquet's mid-range tension. It's comfortable, forgiving, and gives you a responsive stringbed that helps develop your game from day one. Synthetic gut works on a tight budget, but multifilament is a noticeable performance upgrade that's worth the extra cost.

Intermediate: Once you've developed consistent strokes and know what you like, experiment. If you want more spin, try a soft co-poly at a lower tension. If you're already on multifilament and happy with the feel, stick with it and fine-tune your gauge and tension instead of switching types.

Advanced: Most advanced players gravitate toward polyester or hybrid setups. At this level, you're generating enough racquet head speed to compress a stiffer string and benefit from the control and spin it provides.

By Style

Heavy topspin baseliner: Polyester in a thinner gauge (17 or 17L), strung at the lower end of your range. The thin gauge adds spin, and the lower tension keeps the stringbed elastic enough to pocket the ball.

Flat hitter: Full-bed poly at mid-to-higher tension, or a firmer synthetic gut. You want a tight, predictable stringbed that doesn't add too much to the ball's trajectory.

Serve-and-volley: Natural gut or a gut/poly hybrid. Gut's elasticity rewards quick, compact swings and gives you the feel and touch for volleys that poly can't match.

By Priority

Power: Lower tension, thinner gauge, softer string (gut or multifilament).

Control: Higher tension, thicker gauge, stiffer string (polyester).

Comfort: Multifilament or natural gut, lower tension, thinner gauge.

Durability: Thicker-gauge polyester (15L or 16), mid-range tension.

Spin: Shaped or textured polyester in a thinner gauge (17 or 17L), lower tension.

If You Have Arm Pain or Tennis Elbow

String choice is the fastest equipment adjustment you can make for arm comfort. The general approach: softer string type, thinner gauge, lower tension. That means moving toward multifilament or natural gut, dropping your gauge from 16 to 17 or 17L, and pulling your tension down 3-5 lbs from where you normally sit.

If you're currently playing with a full bed of stiff polyester and your arm hurts, that string is almost certainly making it worse. A hybrid setup with gut or multi in the crosses is a good first step if you're not ready to leave poly entirely.

How Often Should You Restring?

The rule of thumb: Restring as many times per year as you play per week. If you play three times a week, aim for at least three restrings per year.

That guideline is a floor, not a ceiling. Players who hit hard, use polyester, or play in extreme heat may need to restring more often.

Breaking Strings Is a Good Sign

A lot of players treat a broken string like something went wrong. It's actually the opposite. If you're snapping strings, it means you're generating real racquet head speed, putting spin on the ball, and making the strings work the way they're supposed to. The friction between mains and crosses during heavy topspin is what causes notching and eventual breakage. That's a sign your technique is doing its job.

The worst thing you can do is react to a few broken sets by switching to a much stiffer or thicker string you don't need. Moving to a stiff poly because you broke a multifilament every couple of months trades comfort, feel, and arm health for durability you probably didn't need in the first place. A better approach: keep the string type that plays well for your game, budget for regular restrings, and treat breakage as a normal part of playing tennis at a high effort level.

When Polyester Goes Dead

Poly strings lose playability faster than they lose structural integrity. A poly setup can feel boardy and lifeless weeks before the strings actually snap. If your shots start landing shorter, you're losing spin, or the stringbed feels wooden on contact, the strings are dead even if they look fine. Most poly players find their strings lose noticeable performance within 10-20 hours of play, depending on the gauge, the brand, and how hard they swing.