Question: how to calculate tension in a guitar string?
Answer: To calculate the tension of a string in pounds use the formula below, inserting the three variables described above: T (Tension) = (UW x (2 x L x F)2) / 386.4 To convert the result into Newtons, simply multiply by 4.45. If you know what tension you want the string to have, you can calculate the string unit weight.