Buy multifilament if your arm matters and synthetic gut if your budget does. Multifilament is hundreds of fine fibers bundled together, which makes it the most comfortable string you can buy without paying for natural gut — and it is the right call for anyone with a sore elbow or over about 45. Synthetic gut is a single solid nylon core with a wrap around it: it costs roughly half as much, lasts a little longer, holds tension respectably and is harsher. For a 3.0 to 3.5 player with a healthy arm who restrings twice a year, synthetic gut is the sensible default. For everyone else, the extra few dollars per restring buys the single biggest comfort upgrade available at this price.
That is the verdict. The sections below are the construction difference it comes from, the honest comparison table, and the three situations where the general answer flips.
What each one actually is
Synthetic gut is a solid monofilament nylon core with one or more outer wraps of thinner filaments. Prince's Duraflex version is the archetype: a solid core with a Duraflex wrap. The solid core is why it is cheap, durable and consistent — and also why it is relatively stiff. It is the string most racquets come pre-strung with and the string most club shops use by default, which is not an accident: it is genuinely good value.
Multifilament replaces that solid core with hundreds (sometimes thousands) of fine fibers twisted and bonded together, in deliberate imitation of natural gut's bundled structure. Each fiber flexes independently, so the whole string stretches more and absorbs more impact energy. Wilson's NXT and Sensation and HEAD's Velocity MLT are all this construction. That is where the comfort comes from and also where the fragility comes from: once the outer fibers abrade, the bundle frays and the string dies visibly.
Both are nylon-family strings. Both are "soft" strings compared to polyester. The difference is architecture, not material, and architecture is what you feel.
Side by side
| Property | Multifilament | Synthetic gut |
|---|
| Construction | Hundreds of fine fibers, twisted and bonded | Solid nylon monofilament core with an outer wrap |
| Comfort | Highest of any non-gut string | Moderate; noticeably firmer |
| Power | High — more stretch means more free depth | Moderate and predictable |
| Feel | Soft, cushioned, a longer dwell time | Crisp and a little muted |
| Tension maintenance | Good at first, then softens as the bundle settles | Good and steady; the solid core holds its shape |
| Durability | Lower; frays visibly once the outer fibers abrade | Higher at the same gauge |
| Spin potential | Low — it grips the ball but does not snap back | Low |
| Typical cost per restring | Roughly double synthetic gut | The cheapest real string there is |
| Best for | Sore arms, older players, comfort-first club play | Budget club play, juniors, pre-strung replacements |
Tension maintenance: the one place synthetic gut genuinely wins
Every string loses tension. TennisCompanion's reference on replacing strings puts the immediate drop at roughly 10 percent in the first 24 hours after stringing, and treats a 10 to 15 lb (about a 30 percent) loss as the point at which a restring is overdue. It also notes that polyester is notorious for losing tension fast, while natural gut has best-in-class tension maintenance.
The two strings on this page sit between those poles, and they fail differently. Synthetic gut's solid core resists creep well, so it holds a fairly steady tension until the wrap wears. Multifilament starts comfortable and gets progressively softer as the fiber bundle settles, so it feels powerful in week two and mushy by week eight, and depth control goes first.
That has a practical consequence: multifilament rewards restringing on a schedule rather than on breakage. If you are the sort of player who restrings only when a string snaps, synthetic gut will serve you better — it stays closer to the same string for longer. Our restring frequency guide has the published table.
Cost, properly calculated
The per-set price is misleading because the two strings live different lengths of time. The number that matters is cost per month of acceptable play.
Buy reels, not sets. This is where the real saving is, and it applies to both. A 200 m reel of NXT is roughly 16 string jobs; a reel of Prince Synthetic Gut is similar. Per restring, a reel is a fraction of a set, and if you are paying a shop for labor anyway you can supply your own string. For anyone restringing three or more times a year, a reel makes a multifilament cost about what synthetic gut costs in sets.
Gauge is the other lever. TennisCompanion's gauge reference gives the standard chart — 16 gauge is 1.26 to 1.34 mm, 17 is 1.16 to 1.24 mm — and notes that thicker string is more durable and longer lasting. So if you break multifilament too fast, go to 16 gauge before you abandon the string type: a 16g multifilament will often outlast a 17g one by enough to change the arithmetic. The same source notes that the studies on gauge and stringbed stiffness have been inconclusive, so do not expect a thinner gauge to solve a comfort problem by itself.
Three situations where the general answer flips
1. You have tennis elbow. Buy multifilament, at the lowest tension in your frame's range, and do not think about the price. The AAOS describes tennis elbow as overuse causing microtearing of the forearm tendons at the elbow, and reports that approximately 80 to 95% of patients succeed with nonsurgical treatment — which makes the equipment side worth getting right. String is the cheapest and largest lever you have. See strings for tennis elbow.
2. You break strings every three weeks. Then neither of these is your string and this is the wrong page. A heavy topspin hitter who shreds nylon needs polyester, which trades comfort for durability and spin — read poly vs multifilament. The honest middle path is a hybrid: polyester in the mains for durability, multifilament in the crosses for comfort.
3. You are stringing a junior's racquet, or a second frame. Synthetic gut, every time. A junior will outgrow the frame before the string matters, and nobody should put a premium multifilament in a backup racquet that lives in a car.
And the string above both of them
Worth naming for completeness, because the whole reason multifilament exists is to imitate it: natural gut is still the most comfortable and most elastic string made, with the best tension maintenance of anything. It costs several times a multifilament and it genuinely dislikes damp weather. If comfort is a medical requirement rather than a preference, and the cost is tolerable, it is the real answer — a gut-and-poly hybrid is what a large share of the professional tour plays. Everyone else: multifilament gets you most of the way there for a fraction.
For the wider map, including polyester and the hybrids, types of tennis strings is the taxonomy and how to choose tennis strings is the decision tree. For the number that matters as much as the string itself, see the tension guide: a multifilament strung tight is less comfortable than a synthetic gut strung loose, which is the most common way players waste money on string.
