Portuguese guitar string tension
A Lisbon Portuguese guitar carries twelve steel strings on a 440 mm scale. In the Galli FG006 Fado Lisboa set they run from .009 to .036, and in Lisbon tuning the calculator puts about 172 lb (78 kg) on the neck, from 12.6 lb on the .013 strings to 19.2 lb on the plain .018 of the bass course.
Tension of the Galli FG006 Lisbon set, string by string
Lisbon tuning on a 440 mm scale, from the 1st course; calculated from D'Addario unit weights for Galli's gauges.
| String | Note | Gauge | kg | lb |
|---|---|---|---|---|
| 1 | B4 | .009 | 6.2 | 13.6 |
| 2 | B4 | .009 | 6.2 | 13.6 |
| 3 | A4 | .010 | 6.0 | 13.3 |
| 4 | A4 | .010 | 6.0 | 13.3 |
| 5 | E4 | .013 | 5.7 | 12.6 |
| 6 | E4 | .013 | 5.7 | 12.6 |
| 7 | B4 | .009 | 6.2 | 13.6 |
| 8 | B3 | .020w | 6.4 | 14.2 |
| 9 | A4 | .010 | 6.0 | 13.3 |
| 10 | A3 | .024w | 7.4 | 16.3 |
| 11 | D4 | .018 | 8.7 | 19.2 |
| 12 | D3 | .036w | 7.3 | 16.0 |
How to use it
- The page opens with the Portuguese guitar, the Galli FG006 set and Lisbon tuning, D A B E A B.
- Choose Coimbra to see the same strings a whole step lower, or load the Fernandez chart to compare.
- Type 470 mm if you have a Coimbra guitar: tension grows with the square of the length.
Help and explanations
Switch to Coimbra tuning, change a gauge or the scale, and every string is recalculated in kg, lb or N. You can also load the Lisbon string chart published by Fernandez Music.
The Lisbon set, course by course
From the 1st course: two .009 on B4 at about 13.6 lb, two .010 on A4 at 13.3 lb and two .013 on E4 at 12.6 lb. The bass courses are octave pairs: a .020 wound on B3 with a .009 on B4, a .024 wound on A3 with a .010 on A4, and a .036 wound on D3 with a .018 on D4, the tightest string in the set at about 19.2 lb (8.7 kg).
These figures are calculated from D'Addario unit weights for Galli's gauges. They match Galli's own chart within 0.8 % on ten of the twelve strings. On the 4th course, Galli lists 19.7 lb for the .009 and 17.5 lb for the .020, which no scale or octave explains; it looks like an error in their table.
Coimbra tuning on the same strings
Coimbra tuning, C G A D G A, sits a whole step below Lisbon. On the same strings and scale, tension drops by about 21 %, the factor (2^(−2/12))², which makes a Lisbon set feel slack. A Coimbra guitar also has a longer scale, about 470 mm, which brings part of that tension back: compare both changes here before you string a Coimbra guitar with a Lisbon set.
Tips
- Measure the scale first: 440 mm and 450 mm Lisbon guitars differ by about 5 % in tension with the same strings.
- Thin plain strings such as the .009 break more easily when brought up to pitch fast; tune up gradually.
- Tune each course with the Portuguese guitar tuner, in Lisbon or Coimbra tuning.
Frequently asked questions
What gauge strings does a Portuguese guitar use?
The Galli FG006 Lisbon set uses .009, .010 and .013 in unison pairs on the treble courses, then .020w with .009 on B, .024w with .010 on A and .036w with .018 on D.
How many strings does a Portuguese guitar have?
Twelve, in six double courses. The three bass courses are octave pairs, the three treble courses unison pairs.
What is the tuning of a Portuguese guitar?
Lisbon tuning from the 6th course to the 1st: D A B E A B (D3 + D4, A3 + A4, B3 + B4, E4, A4, B4). Coimbra tuning is a whole step lower: C G A D G A.
How much tension is on a Portuguese guitar?
About 172 lb (78 kg) for a Galli Lisbon set on a 440 mm scale, by this calculator, which is close to a steel-string acoustic with light strings.
Can I use Lisbon strings on a Coimbra guitar?
They fit, but in Coimbra tuning they lose about 21 % of their tension on the same scale. The longer Coimbra scale makes up part of it; check the result here or use a set made for Coimbra.