String Tension Lab
String tension calculator
Pick a set, tuning and scale, or edit any string. Results update as you change them, and the page address keeps your settings so you can share them.
About these numbers
Tension is calculated, not measured: T = μ · (2 · L · f)², where μ is the string's mass per unit length (unit weight), L the vibrating length (scale) and f the pitch (A4 = 440 Hz, equal temperament). kg means kilogram-force: 1 kg ≈ 9.81 N ≈ 2.205 lb.
How a set feels also depends on the guitar's setup: action height, break angle over the nut and saddle, string length behind the nut and bridge, and your playing style. Plain strings feel stiffer than wound strings at the same tension. Use these figures to compare sets, not as an absolute measure of feel.