Fret Spacing Formula
xn = xo—2 n / 12
The above formula can be used to calculate the required fret spacing, where n is the fret number, xn is the distance of the fret from the bridge and xo is the scale length.
Lots of guitar making books will have tables for popular scales lengths to an accuracy greater than I could ever cut to. However, I just hate rounding errors. Also, by knowing the formula above, any scale length can be created, not just the ones provided. That said, here is a table for a scale length of 25″
| Fret | Inches to bridge |
mm to bridge |
|---|---|---|
| Nut | 25.000 | 635.000 |
| 1 | 23.597 | 599.360 |
| 2 | 22.272 | 565.721 |
| 3 | 21.022 | 533.969 |
| 4 | 19.843 | 504.000 |
| 5 | 18.729 | 475.712 |
| 6 | 17.678 | 449.013 |
| 7 | 16.685 | 423.812 |
| 8 | 15.749 | 400.025 |
| 9 | 14.865 | 377.573 |
| 10 | 14.031 | 356.382 |
| 11 | 13.243 | 336.380 |
| 12 | 12.500 | 317.500 |
| 13 | 11.798 | 299.680 |
| 14 | 11.136 | 282.860 |
| 15 | 10.511 | 266.985 |
| 16 | 9.921 | 252.000 |
| 17 | 9.364 | 237.856 |
| 18 | 8.839 | 224.506 |
| 19 | 8.343 | 211.906 |
| 20 | 7.875 | 200.012 |
| 21 | 7.433 | 188.787 |
| 22 | 7.015 | 178.191 |
| 23 | 6.622 | 168.190 |
| 24 | 6.250 | 158.750 |
The following form can be used to calculate a table for any desired scale length. It uses the formula above and generates the measurements for 24 frets. Simple enter the scale length, and press the button.