Guitar String Tension
Calculate guitar string tension in pounds and newtons for any gauge, scale length, and tuning. Features charts and breakdown for musicians and luthiers.
About This Calculator
The Guitar String Tension Calculator helps musicians, luthiers, and guitar enthusiasts determine the exact tension on any guitar string based on scale length, tuning, string gauge, and material. Understanding string tension is essential for achieving the right feel and playability on your instrument — whether you are a beginner setting up your first guitar or a professional choosing the perfect string set for a custom build.
The tension on a guitar string is governed by the physics formula T = (f × 2 × L)² × μ / g, where f is the frequency in Hz, L is the scale length in inches, μ is the unit weight (linear density) of the string in lb/in, and g is the gravitational acceleration (386.09 in/s²). The unit weight itself depends on the string gauge (diameter) and the material density — for example, a 0.010-inch plain steel string has a unit weight of approximately 0.00002215 lb/in.
Scale length is the vibrating length of the string between the nut and the bridge. Common scale lengths include 25.5 inches (Fender Stratocaster, Telecaster), 24.75 inches (Gibson Les Paul, SG), and 25.0 inches (PRS). Longer scale lengths require higher tension for the same pitch, which can make strings feel stiffer but also improves clarity and sustain.
The calculator supports seven common string materials: Plain Steel, Nickel-plated Steel, Stainless Steel, Phosphor Bronze, 80/20 Brass, Clear Nylon, and Silver-plated Copper Wound. Each material has a different density that affects the unit weight and resulting tension. Nylon strings, for example, have nearly 7× lower density than steel, producing much lower tension ideal for classical guitars.
Regional notes: Tension is displayed in both pounds-force (lb) and newtons (N). While pounds are commonly used in the US and UK for guitar specifications, the newton value is included for scientific and metric-system users worldwide. The formula applies universally regardless of region. String gauge measurements are always in inches (fractional), which is the global industry standard for guitar strings.
Frequently Asked Questions
How do I calculate guitar string tension?
Guitar string tension is calculated using the formula T = (f × 2 × L)² × μ / g, where f is the frequency in Hz, L is the scale length in inches, μ is the unit weight of the string in lb/in, and g is the gravitational acceleration (386.09 in/s²). Enter your guitar's scale length, desired note, string gauge, and material to get the tension in pounds or newtons.
What is normal guitar string tension?
On a typical 25.5-inch scale electric guitar with medium-gauge strings in standard tuning, each string carries between 16 and 20 pounds of tension. Heavier gauge strings and longer scale lengths increase tension, while lighter strings and shorter scales reduce it.
How can I reduce guitar string tension?
You can reduce string tension by switching to a lighter gauge string set, tuning down a half-step or full step, or using a guitar with a shorter scale length. Lighter strings and lower tunings both decrease the tension required to reach pitch.
What is unit weight in guitar strings?
Unit weight, also called linear density, is the weight per unit length of a guitar string, typically measured in pounds per inch or kilograms per meter. It depends on the string's gauge (diameter) and the material density. Thicker strings and denser materials like steel have higher unit weights, requiring more tension to reach the same pitch.
What string materials affect tension the most?
String material density directly affects tension. Plain steel is the lightest common material at 0.2836 lb/in³, while silver-plated copper wound strings are denser at 0.3215 lb/in³. Nylon strings are much lighter at 0.0415 lb/in³, producing far lower tension for the same gauge and pitch. Phosphor bronze and brass fall between steel and copper in density.
How does scale length affect string tension?
Scale length has a squared effect on tension in the formula T = (f × 2 × L)² × μ / g. Doubling the scale length quadruples the tension for the same string and pitch. A 25.5-inch Fender scale requires noticeably more tension than a 24.75-inch Gibson scale for the same tuning.
What is balanced tension in guitar strings?
Balanced tension refers to a set of guitar strings where each string has roughly equal tension when tuned to standard pitch. This creates a more consistent feel across all strings, making barre chords and bends more predictable. Many manufacturers sell balanced tension sets with carefully selected mixed gauges.
What is the difference between tension in pounds and newtons?
Tension is measured in both pounds-force (lb) and newtons (N). One pound-force equals approximately 4.448 newtons. This calculator provides both units so musicians in any country can use the result. Typical guitar string tension ranges from 16-20 lb (71-89 N) per string on a standard electric guitar.