String Tension Calculator

What string tension actually does

String tension is how tightly the strings are pulled when your racket is strung, measured in pounds or kilograms. It is the single cheapest way to change how a racket plays, and unlike buying a new frame you can experiment with it every time you restring. The same racket can feel like a trampoline or a plank depending on the number your stringer dials in.

The short version is that lower tension gives you more power and comfort, while higher tension gives you more control and a crisper feel. The rest is about matching the number to your strings, your swing and your arm. This calculator takes your frame's printed range and nudges it based on those factors so you have a sensible starting point rather than a guess.

Lower tension versus higher tension

When the string bed is looser, the strings stretch more on contact and sling the ball back with extra energy. That means more depth for the same swing, a softer feel that is easier on the arm, and a slightly larger sweet spot. The trade-off is control: on hard, flat swings a loose bed can send the ball long because it rebounds so freely.

A tighter string bed does the opposite. It deforms less, so it returns less of its own energy and gives you a more predictable, connected feel. You get better control and a sharper response on touch shots, at the cost of some power and some comfort, because a stiff bed passes more shock to the hand. Most players find their preference by moving a few pounds at a time and noticing which way the ball starts to misbehave.

Start from your frame's printed range

Every racket has a recommended tension range printed on the frame, usually on the inside of the throat, given as something like 50 to 60 pounds. That range exists for a reason: string too low and the bed can feel mushy and unresponsive, string too high and you risk a harsh feel and extra stress on the frame and your arm.

The calculator asks for that minimum and maximum first, then works inside it. It starts at the midpoint of your range, applies adjustments for your string, style and level, and then clamps the result so it never falls outside the printed limits. Whatever number it gives you, it is a tension the manufacturer already considers safe for that frame.

How the recommender builds your number

The starting point is the middle of your frame's range. From there the tool applies a few offsets. Your string type matters most, since some materials need to be strung looser or tighter to play their best. Your playing style shifts the number toward power or control, and your level makes a small allowance for how consistently you swing.

After adding those offsets, the result is clamped back inside your printed range, and the tool shows a small band around the target rather than a single figure. That band is deliberate. Stringing is not surgery, and a couple of pounds either way is a reasonable window to experiment in. Treat the middle of the band as your first restring and adjust from there.

String type changes everything

Different string materials behave so differently that the same tension number means different things depending on what is in the racket. Polyester, also called co-poly, is stiff and low-powered, so it is almost always strung several pounds lower than other strings to bring back some comfort and depth. String poly at the top of your range and it can feel like concrete and punish the arm.

Multifilament and natural gut are soft and lively, so they can take a slightly higher tension and still feel comfortable, which helps players who want control without a harsh feel. Synthetic gut sits in the middle as a neutral all-rounder. Hybrid setups, which pair a poly in one direction with a softer string in the other, usually get a small downward nudge to protect the arm from the poly half.

• Polyester / co-poly: string lower for comfort and power; it is stiff and low-powered on its own.
• Multifilament and natural gut: soft and forgiving, comfortable even at higher tensions.
• Synthetic gut: a balanced, neutral baseline.
• Hybrid: nudge down a touch to soften the poly half.

Match tension to your playing style

How you swing decides which way to lean. Big, fast, spin-heavy swings benefit from a slightly lower tension, because the extra rebound adds power and the strings snap back to bite the ball for spin. If you are a powerful ball-striker who plays flat and needs the ball to land in, a lower bed can feel too wild, so the tool only drops the number for spin-and-power styles.

Control players who rely on placement, touch and consistency do better a little tighter, where the string bed gives back exactly what you put in. All-court players who mix it up sit in the middle, which is why the tool leaves their number at the midpoint before other factors move it.

Skill level and why it nudges the number

Level is the smallest factor, but it earns a place. Beginners tend to swing shorter and slower and hit off-centre more often, so a slightly lower tension helps in two ways: it adds free power to make up for the shorter swing, and it enlarges the sweet spot so mis-hits are more forgiving. That is why the tool drops the tension a little for beginners.

Intermediate and advanced players generate their own power and place the ball deliberately, so they do not need the extra help and are left at the style-adjusted number. If you are improving quickly, expect your ideal tension to creep up over time as your swing gets longer and more repeatable.

Pounds and kilograms, and the converter

Stringing is quoted in pounds in much of the world and in kilograms elsewhere, which causes plenty of confusion when you read a spec sheet or brief a new stringer. One pound is about 0.4536 kilograms, so 55 pounds is roughly 24.9 kilograms and 24 kilograms is about 52.9 pounds.

The converter at the top of the page handles this both ways so you can talk to any stringer without doing mental arithmetic. Enter a pound figure to see the kilogram equivalent, or the other way round. When you hand your racket in, give both numbers and the string you want, so nothing is lost in translation.

Tension loss and when to restring

Strings start losing tension the moment they are pulled, and the drop is fastest in the first day or two. Polyester in particular sheds tension quickly and goes dead well before it breaks, which is why players who never snap strings still need to restring. A racket that has felt powerless and unpredictable lately is often just strung with tired strings, not badly set up.

A common rule of thumb is to restring as many times per year as you play per week, so twice a week means about two restrings a year at a minimum. If you use poly, restring more often than that, because it loses its playability long before it frays. Keeping a note of the tension and string you used makes each restring a small experiment rather than a reset.

Comfort, the arm and a word on poly

If your elbow or shoulder has been complaining, tension is one of the first dials to turn. Dropping a few pounds and moving to a softer string is a proven way to reduce shock without changing your technique. Full polyester at high tension is the harshest common setup, and for arm-sensitive players it is the first thing to change.

Comfort and control pull in opposite directions, so the aim is the highest tension your arm is happy with, not the highest the frame allows. Start in the lower half of the recommended band, play a few sessions, and only tighten up if you find the ball flying on you. Pair this with a correctly sized, cushioned grip and you have covered the main levers a recreational player can reach.