MusicReasonPitch, Tuning, Intonation, and Fret Geometry
How much does tension change with this gauge swap?
Declare an old and a new string unit weight, plus the shared scale length and target pitch. This tool runs the same tension formula twice and reports the difference. It does not infer unit weight from a gauge number, and it offers no advice about breakage, setup, or instrument health.
Answer
Understand
Switching a string gauge at the same pitch changes tension because it changes the string's unit weight, not because it changes anything about the note being played. A heavier string at the same pitch needs more tension to reach that pitch than a lighter one does, which is the whole reason players compare gauges before committing to a change on an instrument.
Worked examples
Comparing a gauge against itself, with identical old and new unit weights,always reports zero change, confirming the comparison is symmetric and introduces no hidden bias. Doubling the unit weight while holding scale length and frequency fixed exactly doubles the tension, a 100% increase.
Method and limitations
Both the old and new tensions use the identical T = UW × (2Lf)² formula String Tension Calculator uses, evaluated at full precision before taking their difference, so no intermediate rounding step can distort a small percentage change. This tool does not infer a unit weight from a nominal gauge number for either string, and it makes no recommendation about whether a given gauge change is safe for a specific neck, bridge, or nut; that judgment depends on factors this tool has no way to observe.
Because tension scales with the square of unit weight, a modest-sounding gauge bump can produce a larger tension increase than expected: moving from a lighter to a noticeably heavier core wire can raise tension by 30% or more even though the gauge numbers themselves might only differ by a few thousandths of an inch. Reporting both the absolute newton difference and the percent change together lets a player judge the swap by whichever framing matches how they think about their instrument's feel.