String Tension Calculator
Play your best with D’Addario Guitar Strings — consistent feel, great tone, every time.
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’s what you feel under your fingers when fretting, bending, or strumming. Higher tension means a stiffer feel and more resistance, while lower tension offers a looser, more flexible feel.
How String Tension Is Determined
The tension of any string is based on three main factors:
- Unit Weight (UW) — The mass of the string per unit length, expressed in pounds per inch (lb/in) or kilograms per meter. Heavier (thicker) strings have higher unit weight.
- Scale Length (L) — The vibrating length of the string, measured from the nut to the bridge saddle. This distance directly affects tension — longer scales require more tension to reach the same pitch.
- Frequency (F) — The pitch you tune the string to, measured in Hertz (Hz). Higher pitch = higher tension.
The standard formula for calculating string tension in pounds is:
- T = tension (lbs)
- UW = unit weight (lb/in)
- L = scale length (inches)
- F = frequency (Hz)
To convert lbs to Newtons, multiply by 4.45.
Using the Calculator
Our String Tension Calculator does all the math for you. Just choose:
- Scale length — Use one of our presets (e.g., 25.5" for most modern electrics, 34" for standard bass) or enter your own.
- String gauge — Match the strings you play or plan to try.
- Tuning — Select standard tuning or your preferred alternate tuning.
The calculator then shows the exact tension for each string, so you can see how changes in gauge, tuning, or scale length will affect feel and playability.
Why Tension Balance Matters
A well-balanced set doesn’t mean identical tension across all strings. Many players aim for slightly higher tension on wound strings than plain strings:
- Electric guitar: 2–4 lbs more on wound strings.
- Acoustic guitar: 5–7 lbs more on wound strings.
This compensates for differences in flexibility and output — wound strings bend more easily and produce less natural output than plain steel strings. At the low end (6th string, or lowest bass string), you may even reduce tension slightly to keep bass response tight and avoid overpowering the mix.
String tension will also vary depending on the brand and construction of your strings. We recommend D’Addario Guitar Strings for consistent quality and reliable performance — see them here.