Cuatro fret calculator
The Venezuelan cuatro is a small four-string nylon instrument, and its scale length is not standardized. Aquila's string chart is written for a 51 cm (510 mm, about 20.08″) cuatro, so this calculator starts there, with 17 frets as on a concert cuatro; traditional cuatros usually have 14 or 15, and TuCuatro describes 17-fret models built on a 15-fret neck.
Venezuelan cuatro fret positions, 510 mm scale
17 equal-tempered frets measured from the nut, on Aquila's 51 cm reference scale.
| Fret | From nut (mm) | From previous (mm) | To saddle (mm) |
|---|---|---|---|
| 1 | 28.62 | 28.62 | 481.38 |
| 2 | 55.64 | 27.02 | 454.36 |
| 3 | 81.14 | 25.50 | 428.86 |
| 4 | 105.21 | 24.07 | 404.79 |
| 5 | 127.93 | 22.72 | 382.07 |
| 6 | 149.38 | 21.44 | 360.62 |
| 7 | 169.62 | 20.24 | 340.38 |
| 8 | 188.72 | 19.10 | 321.28 |
| 9 | 206.75 | 18.03 | 303.25 |
| 10 | 223.77 | 17.02 | 286.23 |
| 11 | 239.84 | 16.06 | 270.16 |
| 12 | 255.00 | 15.16 | 255.00 |
| 13 | 269.31 | 14.31 | 240.69 |
| 14 | 282.82 | 13.51 | 227.18 |
| 15 | 295.57 | 12.75 | 214.43 |
| 16 | 307.61 | 12.03 | 202.39 |
| 17 | 318.97 | 11.36 | 191.03 |
Aquila Corde, ethnic instrument strings chart (Venezuelan cuatro, 51 cm)
How to use it
- Tap Venezuelan cuatro 510 mm, or type your own scale length: measure from the nut to the 12th fret and double it, before any saddle compensation.
- Set the number of frets: 14 or 15 for a traditional cuatro, 17 for a concert model.
- Leave the compensation on nylon and read the fret table: from the nut, from the previous fret and to the saddle.
- Tap Print template at 100% and measure the 100 mm bar before you mark the fretboard.
Help and explanations
On a 510 mm scale the 1st fret sits 28.62 mm from the nut, the 12th exactly at half the scale, 255.00 mm, and the 17th at 318.97 mm. Change the scale or the fret count and the table and the full-size template follow.
What scale length is a cuatro?
Published figures differ by about 2.5 cm. Aquila sizes its Venezuelan cuatro strings for 51 cm, while Thomann lists about 48.5 cm (485 mm) for its Cuatro Venezolano Standard. On 485 mm the 12th fret moves to 242.50 mm, 12.50 mm closer to the nut than on 510 mm, which is far too much to ignore when you slot a fretboard. Measure your own instrument instead of trusting a nominal figure.
The Puerto Rican cuatro is a different, larger instrument with 10 steel strings in five courses. The Smithsonian's record of a cuatro by Rafael Avilés Vázquez gives a 51.5 cm scale; on 515 mm the 12th fret falls at 257.50 mm and the 20th at 352.79 mm. Wikipedia mentions 18 to 20 frets, without a citation, so treat that count as an estimate.
How the positions are calculated
Each fret sits where the string is shortened by one equal-tempered semitone: d = L − L ÷ 2^(n/12), the formula R. M. Mottola publishes and the StewMac fret calculator uses. Always measure every fret from the nut, never by adding up the gaps, or small ruler errors build up along the board. A nylon-strung cuatro needs roughly 1.5 to 3 mm of saddle compensation; set the final position with the 12th-fret octave once it is strung.
Tips
- A cuatro's 1st string, B3, is lower than the 2nd, F♯4: check the strings for your scale in the cuatro string tension calculator.
- Once it is strung and tuned, compare the 12th fret with the octave using the intonation checker.
- Restringing a finished cuatro? Follow the cuatro string change guide.
Frequently asked questions
What is the scale length of a Venezuelan cuatro?
Around 485 to 510 mm (19.1″ to 20.1″). Aquila's string chart uses 51 cm; Thomann's Cuatro Venezolano Standard is about 48.5 cm.
Where is the 12th fret on a cuatro?
At exactly half the scale: 255.00 mm (10.04″) from the nut on a 510 mm cuatro, 242.50 mm on a 485 mm one.
How many frets does a cuatro have?
A traditional Venezuelan cuatro usually has 14 or 15 frets, a concert cuatro 17. On a 510 mm scale the 17th fret is 318.97 mm from the nut.
What is the scale length of a Puerto Rican cuatro?
The Smithsonian's Avilés Vázquez cuatro measures 51.5 cm (515 mm). Its 12th fret falls at 257.50 mm from the nut.
How far is the 1st fret from the nut on a cuatro?
28.62 mm (1.127″) on a 510 mm scale, and 27.22 mm on a 485 mm scale.