Guitar String Tension Calculator

Enter the scale length, the note the string is tuned to and either its gauge or its unit weight, and this returns the tension in pounds, kilograms-force and newtons, along with what the same string pulls a semitone either side. The equation behind it is exact, but the unit weight is not: a plain steel string follows from its diameter, while a wound string has a core and a wrap in unknown proportion and needs the figure from the maker's own tension chart, which is why that is an input rather than a lookup. A second action works the other way and gives the plain steel gauge a target tension calls for at a given pitch and scale. It is the number to check before committing to a drop tuning or a new gauge, since tension moves with the square of both the pitch and the scale length.