Bass String Tension Calculator

About this calculator

String tension is found from a standard string-physics formula: T = (UW × (2 × L × f)²) ÷ 386.4, where UW is the string's unit weight (mass per unit length, from the manufacturer's gauge data), L is scale length in inches, f is the target frequency in Hz, and 386.4 is the gravitational constant in inches/sec² used to convert the result to pounds of tension.

Because tension depends on the square of both scale length and frequency, small changes in tuning or scale length shift string feel dramatically — which is why a 34-inch scale bass tuned to standard E-A-D-G feels noticeably different strung on a 30-inch short-scale instrument even with the same gauge strings. Bass players choosing string gauges, luthiers setting up instruments, and string manufacturers use tension calculations like this to match playing feel across different scale lengths, tunings, or drop-tuning setups.