How is guitar string tension calculated?

Tension = (unit weight of the string × (2 × frequency × string length)²) ÷ gravitational constant, based on the string's gauge, scale length, and target pitch.

Why does string tension matter for playability?

Higher tension strings feel stiffer and require more finger pressure, while lower tension strings feel looser — tension affects both playing feel and tone.

Does tuning a string up or down change its tension?

Yes — tuning higher increases tension, and tuning lower decreases it, which is why alternate tunings often call for different string gauges to maintain comfortable tension.

Guitar String Tension Calculator

Every guitar string needs a specific amount of tension to reach its intended pitch, based on its thickness (unit weight), the guitar's scale length, and the target tuning frequency.

String Unit Weight (lb/in)

Scale Length (inches)

Tuning Frequency (Hz)

Instant Result

String Tension -

What Is a Guitar String Tension Calculator?

Every guitar string needs a specific amount of tension to reach its intended pitch, based on its thickness (unit weight), the guitar's scale length, and the target tuning frequency. Knowing string tension helps guitarists choose string gauges that feel and play consistently, especially when switching tunings.

How to Use This Guitar String Tension Calculator

Look up the string's unit weight in pounds per inch (published in most string manufacturers' spec sheets).
Enter your guitar's scale length in inches (25.5" is standard for a Fender-style guitar, 24.75" for many Gibson-style guitars).
Enter the target tuning frequency in Hz for that string (e.g. 82.41 Hz for a standard low E).
Click Calculate to get the string tension in pounds.

Formula

Tension (lbs) = Unit Weight × (2 × Scale Length × Frequency)² / 386.4

Worked Example

A low E string with a unit weight of 0.00035 lb/in, a 25.5" scale length, tuned to 82.41 Hz. Tension = 0.00035 × (2×25.5×82.41)² / 386.4 ≈ 16.0 lbs — a typical, comfortable tension for a low E string.