Guitar String Tension Calculator
Why String Gauge and Tuning Both Matter
Two guitars strung with the same gauge set can feel completely different under the fingers if they're tuned differently, and two strings tuned to the same note can pull with very different force if their gauges differ. Tension is what actually determines how a string feels to bend and how much load it places on the neck and bridge — not gauge or pitch in isolation, but the combination of both, along with scale length and the material the string is made from.
The Formula
Tension = UW × (2 × Scale Length × Frequency)² ÷ 386.4
This is the standard D'Addario-style string tension formula. Unit weight is derived from the string's cross-sectional area and its material density, and 386.4 in/s² is the gravitational constant used to convert the result into pounds of force. Density varies by construction — plain steel, nickel-wound, pure nickel-wound, phosphor bronze, and stainless-wound strings each use a different value, since the value is derived from the material's own mass characteristics.
Where This Calculation Matters
- Choosing a string gauge — guitarists moving to a lower tuning often size up gauge specifically to keep total tension, and therefore playing feel, close to what they're used to.
- Alternate tunings — dropping a string's pitch reduces its tension roughly with the square of the frequency ratio, which is why a stock set can feel noticeably looser in drop tunings.
- Neck relief and setup — a guitar tech calculating total string-set tension can anticipate how much a gauge or tuning change will affect neck relief and bridge load.
- Building custom sets — players who mix gauges from different packs use this formula to keep tension balanced across the strings rather than guessing.
| String | Gauge (in) | Pitch | Tension |
|---|---|---|---|
| High E | 0.010 | E4 (329.63 Hz) | 16.26 lbs |
| B | 0.013 | B3 (246.94 Hz) | 15.42 lbs |
| G | 0.017 | G3 (196.00 Hz) | 16.61 lbs |
| D (wound) | 0.026 | D3 (146.83 Hz) | 24.73 lbs |
| A (wound) | 0.036 | A2 (110.00 Hz) | 26.61 lbs |
| Low E (wound) | 0.046 | E2 (82.41 Hz) | 24.39 lbs |
Computed using this calculator's own formula (plain strings modeled as plain steel, wound strings as nickel-wound) at a 25.5″ scale length. Wound-string results are estimates — real winding technique and core-to-wrap ratio shift actual tension somewhat from a pure density model.
How to Use This Calculator
- Enter the target frequency of the string in Hz (use the Note Frequency Calculator if you know the note name instead).
- Enter the guitar's scale length in inches, measured from nut to bridge.
- Enter the string gauge in inches (for example, 0.010 for a .010" string).
- Select the string material — plain steel, nickel-plated steel wound, pure nickel wound, phosphor bronze wound, or stainless steel wound.
- Select Calculate to get the tension in pounds and kilograms.
Related Calculations
Look up a string's exact target frequency with the Note Frequency Calculator before running this one, or check interval spacing between open strings with the Interval Calculator.