String Tension Calculator
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What Your Result Means
- Tension (lbs): The pulling force the string exerts on the nut and bridge. Most electric guitar strings land between 12–20 lbs per string; bass strings typically run 30–45 lbs.
- Tension (kg): The same force in metric units, useful if your string manufacturer lists specifications in kilograms.
- Frequency: The fundamental pitch of the open string at standard tuning. This value comes from the note you selected, not from any measurement.
- Balanced set: A well-balanced set generally keeps all strings within a few pounds of each other. Wide tension gaps between strings can make bending inconsistent or cause neck twist.
How This Calculator Works
You enter a scale length, string gauge (diameter in inches), and tuning note. The tool derives the unit weight of a plain steel string from the gauge using the density of music wire (0.284 lb/in³), then applies the Mersenne equation to compute tension. It assumes a plain (unwound) steel string — wound strings have a lower effective density and will show higher tension than their actual value.
Quick Questions
Why does it say "plain steel" — what about wound strings?
Wound strings have a steel core wrapped in a secondary wire, which changes the effective mass per unit length. This calculator uses the plain-steel density, so wound strings (typically the lower 3–4 strings on a guitar) will read higher than their real tension. Manufacturers publish unit-weight charts for wound sets that give more accurate values.
How does scale length affect tension?
Tension rises with the square of scale length. A Fender-scale guitar (25.5″) puts about 6% more tension on the same gauge and pitch than a Gibson-scale (24.75″). This is why shorter-scale guitars often feel "slinkier" with the same string set.
What tension range is comfortable for most players?
Most electric guitarists prefer per-string tension between about 14–18 lbs. Jazz players often go higher (heavier gauges), while shredders and benders tend toward the lower end. There is no single right answer — it depends on playing style, action height, and personal feel.
Can I use this for nylon or other non-steel strings?
No. Nylon, gut, and synthetic strings have very different densities than steel. This calculator's density constant (0.284 lb/in³) is specific to plain steel music wire. Use manufacturer data sheets for non-steel strings.
Sources
- D'Addario String Tension Reference (published unit-weight and tension data for guitar and bass strings)
- Wikipedia — Mersenne's Laws (the physics behind vibrating string frequency and tension)
- Liutaio Mottola — String Tension (luthier reference for tension calculations)
Method & review
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.