String Tension Calculator
Enter your scale length, string gauges, and tuning to see the tension of each string. Use it to plan a new set, try an alternate tuning, or balance the feel across the neck.
What is string tension?
String tension is the amount of force, measured in pounds (lbs) or Newtons (N), that a string exerts when tuned to pitch. For a player, it is what you feel under your fingers when fretting, bending, or strumming. Higher tension gives a stiffer, more resistant feel; lower tension feels looser and more flexible.
How string tension is determined
Tension comes down to three main factors:
- Unit weight (UW). The mass of the string per unit length, in pounds per inch (lb/in). Heavier, thicker strings have a higher unit weight.
- Scale length (L). The vibrating length from the nut to the bridge saddle. Longer scales need more tension to reach the same pitch.
- Frequency (F). The pitch you tune to, in Hertz (Hz). A higher pitch means higher tension.
The standard formula for tension in pounds is:
- T = tension (lbs)
- UW = unit weight (lb/in)
- L = scale length (inches)
- F = frequency (Hz)
To convert pounds to Newtons, multiply by 4.45.
Using the calculator
The calculator does the math for you. Just set:
- Scale length. Pick a preset (25.5" for most modern electrics, 34" for standard bass) or enter your own.
- String gauge. Match the strings you play or want to try.
- Tuning. Choose standard or your preferred alternate tuning.
It then shows the tension for each string, so you can see how a change in gauge, tuning, or scale length affects feel before you buy a set.
Why tension balance matters
A well-balanced set does not mean identical tension across every string. Many players aim for slightly higher tension on the wound strings than the plain ones:
- Electric guitar: about 2 to 4 lbs more on wound strings.
- Acoustic guitar: about 5 to 7 lbs more on wound strings.
This makes up for differences in flexibility and output, since wound strings bend more easily and put out a little less than plain steel. On the lowest string you may even drop the tension slightly to keep the bottom end tight.
A note on brands and accuracy
Tension also varies with a string's brand and construction, so treat any result here as a close estimate rather than an exact figure. When you find a set and tuning that feel right, note the gauges so you can repeat them.