Guitar String Tension Calculator
Calculate each guitar string’s tension in lbf, kgf and newtons from scale length, pitch frequency and the manufacturer’s unit weight, plus the total set tension.
Interactive calculator · Method GUITAR-STRING-TENSION-1.0 · Last reviewed: 2026-11-04
Calculate your scenario
Tension (lb) = unit weight (lb/in) × (2 × scale length (in) × frequency (Hz))² ÷ 386.4, the form used on string makers’ tension charts (386.4 is gravity in in/s²; the standard value 386.09 would read about 0.08% higher).
Your inputs
Default worked example. Edit the inputs to calculate your scenario.
Default worked example
String 1: 0.00002215 × (2 × 25.5 × 329.63)² ÷ 386.4 = 16.2 lbf; 6 string(s) total 103.5 lbf.
How to use the calculator
Enter the scale length, how many strings to include and, for each string, its pitch in Hz and the unit weight from the manufacturer’s chart. Lower each Hz value to model down-tuning.
What the result means
The example 10–46 set in standard E tuning on a 25.5 in scale totals about 103.5 lbf (46.95 kgf), with the A string highest at about 19.52 lbf.
Formula and units
Tension (lb) = unit weight (lb/in) × (2 × scale length (in) × frequency (Hz))² ÷ 386.4, the form used on string makers’ tension charts (386.4 is gravity in in/s²; the standard value 386.09 would read about 0.08% higher). kgf = lbf × 0.45359237; N = lbf × 4.44822.
Worked examples
10–46 set, standard E, 25.5 in scale: Scale length: 25.5 in; Strings to include (1 = string 1 only): 6 strings; String 1 (high E) pitch: 329.63 Hz; String 2 (B) pitch: 246.94 Hz; String 3 (G) pitch: 196 Hz; String 4 (D) pitch: 146.83 Hz; String 5 (A) pitch: 110 Hz; String 6 (low E) pitch: 82.41 Hz; String 1 unit weight (example from a 10–46 set chart): 0.00002215 lb/in; String 2 unit weight (example from a 10–46 set chart): 0.00003744 lb/in; String 3 unit weight (example from a 10–46 set chart): 0.00006402 lb/in; String 4 unit weight (example from a 10–46 set chart): 0.00012671 lb/in; String 5 unit weight (example from a 10–46 set chart): 0.00023964 lb/in; String 6 unit weight (example from a 10–46 set chart): 0.00038216 lb/in.
Example result: Total set tension: 103.5 lbf; Total set tension (kgf): 46.95 kgf; Total set tension (N): 460.4 N; Highest string tension: 19.52 lbf (string 5); Average per string: 17.25 lbf.
Same set on a 24.75 in scale: Scale length: 24.75 in; Strings to include (1 = string 1 only): 6 strings; String 1 (high E) pitch: 329.63 Hz; String 2 (B) pitch: 246.94 Hz; String 3 (G) pitch: 196 Hz; String 4 (D) pitch: 146.83 Hz; String 5 (A) pitch: 110 Hz; String 6 (low E) pitch: 82.41 Hz; String 1 unit weight (example from a 10–46 set chart): 0.00002215 lb/in; String 2 unit weight (example from a 10–46 set chart): 0.00003744 lb/in; String 3 unit weight (example from a 10–46 set chart): 0.00006402 lb/in; String 4 unit weight (example from a 10–46 set chart): 0.00012671 lb/in; String 5 unit weight (example from a 10–46 set chart): 0.00023964 lb/in; String 6 unit weight (example from a 10–46 set chart): 0.00038216 lb/in.
Example result: Total set tension: 97.5 lbf; Total set tension (kgf): 44.23 kgf; Total set tension (N): 433.7 N; Highest string tension: 18.39 lbf (string 5); Average per string: 16.25 lbf.
Limitations and common mistakes
Needs the unit weight from the string maker’s chart for the exact string; the defaults are only an example 10–46 set. Uses the nominal scale length and ignores fret compensation, string stiffness and winding differences. It gives tension figures only, not a judgement of what a neck, bridge or instrument can safely carry.
Entering the string gauge (for example 0.046) in place of the unit weight gives a tension hundreds of times too high.
Sources and assumptions
Method GUITAR-STRING-TENSION-1.0; last formula review 2026-11-04. Sources and their supported claims. Calculation methodology.