String Tension Calculator
See exactly how hard your strings pull. Pick an instrument, gauge set, scale length, and tuning to get per-string and total tension in pounds and kilograms — then compare sets before you buy, or check what a drop tuning does to your low string. Tensions come from published D’Addario unit weights and the standard tension formula.
Calculate your set’s tension
| String | Construction | Gauge | Tension |
|---|---|---|---|
| 6th E2 | Nickel wound | .046 | 17.5 lbs (7.9 kg) |
| 5th A2 | Nickel wound | .036 | 19.5 lbs (8.9 kg) |
| 4th D3 | Nickel wound | .026 | 18.4 lbs (8.3 kg) |
| 3rd G3 | Plain steel | .017 | 16.6 lbs (7.5 kg) |
| 2nd B3 | Plain steel | .013 | 15.4 lbs (7.0 kg) |
| 1st E4 | Plain steel | .010 | 16.2 lbs (7.3 kg) |
| Total tension on the neck | 103.5 lbs (46.9 kg) | ||
How string tension is calculated
Every result uses the standard formula string makers publish:
T = UW × (2 × L × F)² ÷ 386.4
- T — tension in pounds.
- UW — the string’s unit weight in pounds per inch, published per gauge and construction (a wound .026 weighs more per inch than a plain .026, so it pulls harder at the same pitch).
- L — scale length in inches: the vibrating length from nut to bridge.
- F — the pitch frequency in Hz (A440 equal temperament — the same math as our tuner).
Worked example: a plain .010 tuned to E4 (329.63 Hz) on a 25.5" scale has UW = 0.00002215 lb/in, so T = 0.00002215 × (2 × 25.5 × 329.63)² ÷ 386.4 ≈ 16.2 lbs.
What changes tension — and what it means for feel
- Scale length. Longer scale = more tension at the same pitch and gauge. The same 10–46 set pulls about 10% harder on a 25.5" Strat-style neck than on a 24.75" Les Paul-style neck — which is why the same set feels stiffer on one and slinkier on the other.
- Gauge. Heavier strings weigh more per inch, so they need more tension to reach the same pitch. Moving from 9s to 10s adds roughly 10–12% across the set.
- Tuning. Tension falls with the square of frequency: drop D takes the low string down about 20%, and a full step down (D standard) cuts every string by that much — the usual reason drop tunings feel floppy until you go up a gauge. Work out the fretted shapes for a new tuning with the capo & transpose calculator.
- Construction. At the same gauge and pitch, wound strings pull harder than plain because the wrap adds mass. That’s why sets switch from plain to wound around .017–.026.
Typical total pull is 90–110 lbs on an electric set, 150–180 lbs on a medium acoustic set, and 140–160 lbs on a 4-string bass — enough that gauge changes are worth a truss-rod check. New to gauges and sets? Start with the gear guides.