Bass String Tension Calculator

How it is calculated

The tool uses the vibrating-string relation in imperial units: T = UW × (2 × L × f)² / 386.4. UW is the string's unit weight in pounds per inch (from the maker's gauge chart), L is the scale length in inches, f is the pitch in hertz, and 386.4 is the gravitational constant in inches per second squared that turns mass into force. The result is tension in pounds, and the same value times 0.45359237 is shown in kilograms.

Here 2 × L × f is the wave speed along the string. Because the formula squares both scale length and frequency, doubling the pitch multiplies tension by four, and a shorter scale lowers tension a lot at the same pitch. All three inputs must be above zero. The calculation applies to the open string at the given pitch; it does not model fretted notes, string stiffness, or the string's stretch.

Common mistakes

• Entering the unit weight in grams per metre or ounces per foot. The field is pounds per inch, so a value copied from a metric chart will be wildly out and give a nonsense tension.
• Typing the scale length in millimetres or centimetres. It is inches: a 34 inch bass is 34, not 864.
• Using the wrong pitch for the string. A string tuned an octave higher takes four times the tension, so check the frequency for the actual note (41.2 Hz for low E, not 82.4).
• Expecting the result to include everything that affects feel. Tension is only one factor; the stiffness of a thick wound string and the action also change how it plays.
• Comparing sets by single-string tension. A balanced set is judged across all strings, so run the calculation for each one.