String tension calculator
The pull of every string, and which gauges to use for the tuning you want
Tension
Tunings
Fill all the fields on the left and submit, or choose one of the presets below
Guitars
Basses
This calculator gives the pull of every string from three things only: the scale length, the target note and the gauge. The formula is the vibrating string one, with no coefficient to tune, and the only unknown is the mass per unit length of the string.
It also answers the question the other way round, which is the one a low tuning actually raises: not what a set pulls, but which gauges to fit. Pick a tuning, give a target tension, and it proposes a set, string by string, for drop C, drop B, a baritone, a seven or an eight string. Multiscale necks are handled too, with a scale length per string.
Frequently asked questions
How is the tension calculated?
With the vibrating string formula: tension = (2 x scale length x frequency)² x mass per unit length. Nothing in that formula needs tuning, all of the uncertainty sits in the mass per unit length.
Where does the mass per unit length come from?
For a plain string it is computed from the diameter and the density of steel, which is pure geometry. For a wound string the core and the wrap are modelled, which puts a 10-46 set at 25.5 inches within 3 % of the values published by string makers.
Can I check the result at home?
For a plain string, yes, and without weighing anything: measure its diameter with a caliper, that is the only input the calculation uses. For a wound string you would have to weigh a metre of it, which needs a scale reading hundredths of a gram; a kitchen scale reading whole grams only gets you there on heavy bass strings. Otherwise, compare with the tension published by the maker of your set.
What gauge strings should I use for drop C?
On a 25.5 in scale, a normal 10-46 set tuned down to drop C leaves the low string at 5.0 kg where it pulled 8.0 kg in standard E, which is why it feels floppy. The 11-52 preset here brings that string back to 6.5 kg and the whole neck to 42 kg. Load the preset, set your own scale length, and read the tension column rather than trusting a number someone quoted for a different guitar: the same 11-52 on a 24.75 in Gibson scale drops to 39.5 kg.
What gauge for a baritone, a seven string or drop B?
Same method, and the scale length decides more than the gauge does. A 13-60 set at B standard pulls 8.6 kg on the low B at 27 in, but only 7.7 kg at 25.5 in, for the same strings. A seven string in B wants around a .059 for the extra string: that gives 7.4 kg at 25.5 in and 8.0 kg at 26.5 in, compared with 8.0 kg on the low E of a standard set. Drop B with an 11-52 leaves the bottom string at 5.7 kg, which is on the loose side, so go heavier there.
Does the same set feel tighter on a longer scale?
Yes, and it is the largest effect on this page. Tension goes with the square of the scale length, so a 10-46 set in standard E pulls 46.9 kg on a 25.5 in neck and 44.1 kg on a 24.75 in one, six percent less for exactly the same strings and the same notes. That is why gauge advice copied from a forum is only worth what the scale length behind it is worth.
See also the fret calculator and the pickup winding calculator.