Guitar String Tension Calculator
Find the tension on any guitar string given your scale length, string gauge, tuning frequency, and material. Use it when switching tunings or gauges to keep tension balanced across all six strings.
Last updated: September 2026
String Tension
16.31 lbs
Formula below · 2 sources (aes.org, Wikipedia) · Updated Sep 2026
Compare with similar
About this calculator
String tension depends on how fast the string vibrates (frequency), how long the vibrating section is (scale length), and the physical properties of the string itself. The formula used here is the standard one string makers publish: T = UW × (2 × L × f)² / 386.4, where UW is the unit weight (lb per inch of string), L is the scale length in inches, f is the frequency in Hz and 386.4 in/s² is gravity. The unit weight is estimated from the gauge d and the material density ρ as UW = ρ × π × d² / 4, so T = π × ρ × d² × L² × f² / 386.4. A wound string weighs less than a solid rod of the same outside diameter, so wound options use an effective density derived from published unit weights (D'Addario NW026 ≈ 0.239, PB042 ≈ 0.265 lb/in³). Doubling the scale length quadruples the tension for the same pitch — which is why baritone guitars need lighter strings to stay playable. Similarly, tuning down a semitone reduces tension noticeably, while heavier gauges increase it. Balancing tension across all strings is essential for consistent playability and intonation.
How to use
Suppose you have a standard 25.5-inch Stratocaster scale and a plain steel .010 string (density 0.284 lb/in³) tuned to E4 = 329.63 Hz. Step 1: 329.63² = 108,656. Step 2: 25.5² = 650.25. Step 3: 0.010² = 0.0001. Step 4: T = π × 0.284 × 0.0001 × 650.25 × 108,656 / 386.4 ≈ 16.3 lbs of tension — matching the 16.2 lb D'Addario publishes for a PL010 at E4, typical for a light-gauge electric guitar string.
Frequently asked questions
How does scale length affect guitar string tension?
Scale length has a squared relationship with tension — doubling the scale length quadruples the tension required to reach the same pitch. A guitar with a 25.5-inch scale will have noticeably higher string tension than one with a 24.75-inch scale when using identical strings and tuning. This is why many players find shorter-scale guitars feel 'softer' or easier to bend. Choosing the right gauge for your scale length is key to comfortable playability.
What string gauge should I use when drop-tuning my guitar?
When you drop-tune (e.g., from E standard to Drop D or C standard), string tension drops significantly, making strings feel floppy and causing intonation problems. As a general rule, increase gauge by roughly one step for each whole tone you drop — for example, moving from .010s to .011s or .012s. Using this calculator lets you dial in the exact tension you want at your target frequency before buying strings. Aim to match the tension you had at standard tuning for the most consistent feel.
Why do different string materials produce different tensions at the same gauge?
Different materials have different densities, so a .010 wound nickel string and a .010 plain steel string will not produce the same tension at the same pitch and scale length. The density in the formula sets the mass per unit length of the string. Wound strings, which have a core wrapped with metal wire, contain air gaps and weigh less than a solid rod of the same outside diameter, so this calculator uses effective densities for them. For exact figures, use the unit weight your string maker publishes.
Related calculators
Sources & references
Think a result is wrong? Report a problem with this calculator.