AltTuningLab

Calculated starting set

7-String Drop A Gauges for a 25.5-Inch Guitar

On a 25.5-inch seven-string, Drop A puts the lowest string close to the limit where gauge choice becomes especially noticeable. The right answer depends on how much clarity you want from the low A and how stiff you want it to feel.

Tuning
A E A D G B E
Strings
7
Scale length
25.5 in

Recommendation

.010–.064 is the calculated starting point

Begin at .010–.064. It gives the low A more support than a typical .059 or .060 while keeping the upper six strings familiar to players coming from a standard-tuned six-string.

Tension table

Estimated tension at 25.5 inches

Calculated from pitch, gauge, scale length, and a plain or wound construction estimate.

Total pull109.9 lb
Average / string15.7 lb
Set spread3.6 lb
StringPitchGaugeBuildEstimated tension
7A1.064wound13.4 lb
6E2.046wound15.5 lb
5A2.036wound16.9 lb
4D3.026wound15.7 lb
3G3.017plain16.6 lb
2B3.013plain15.4 lb
1E4.010plain16.3 lb

Low-string comparison

Compare nearby gauges at the same pitch

The calculator holds A1 and 25.5 inches constant, then changes only the wound low-string gauge.

.062
12.6 lb
.064 Starting point
13.4 lb
.066
14.2 lb

What it should feel like

Use the table to make a confident adjustment

This practical, medium-feel set provides a comparison baseline. For a lighter touch, compare .062; for aggressive rhythm playing, compare .066. The calculator shows the trade-off instead of relying on a gauge number alone.

Before restringing

Plan for the full guitar setup

  1. 1Confirm that the low-string nut slot supports the chosen gauge without pinching.
  2. 2Check pickup height after a major string change; low strings move in a wider arc.
  3. 3If the low A remains indistinct, compare a longer scale length or a slightly heavier gauge before making an extreme jump.

Common questions

7-string Drop A string-gauge FAQ

Is .064 enough for a 7-string Drop A?
It is a reasonable starting point on a 25.5-inch guitar. Whether it is enough depends on attack, action, and personal feel; use the table to compare it with .062 and .066.
Can I use a regular 7-string set in Drop A?
Some sets are suitable, but inspect the low-string gauge. A set intended for B standard may leave the dropped A looser than you want.