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.
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 T = (4 × f² × L² × μ) / (π × r²), where f is the target frequency in Hz, L is the scale length in inches, μ represents the linear mass density approximated via string gauge, and r is the material radius. 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, a plain steel .010 gauge string (0.010 inches), tuned to E4 = 329.63 Hz, with a material constant of 0.00026 for plain steel. Plug into T = (4 × 329.63² × 25.5² × 0.010) / (π × 0.00026²). Step 1: 329.63² = 108,656. Step 2: 25.5² = 650.25. Step 3: Numerator = 4 × 108,656 × 650.25 × 0.010 ≈ 2,828,400. Step 4: Denominator = π × 6.76×10⁻⁸ ≈ 2.12×10⁻⁷. Result ≈ 16.2 lbs of tension — 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 material constant in the formula accounts for the mass per unit length of the string. Wound strings, which have a core wrapped with metal wire, behave differently from plain strings of the same nominal diameter. Always use the correct material constant for accurate tension calculations.