Multiscale fret calculator
On a multiscale (fanned fret) neck, each string has its own scale length: the bass side is longer so low tunings stay tight, and the treble side is shorter so the high strings don't feel stiff. The frets fan out, with one perpendicular fret, usually around the 7th to 9th, square to the neck.
Fret positions on a 25.5″ to 27″ fan
Distance from the nut to each fret along the outer strings of a 6-string guitar with the 8th fret perpendicular, and the fret angle relative to the perpendicular fret.
| Fret | Bass side (685.8 mm) | Treble side (647.7 mm) | Angle |
|---|---|---|---|
| 1 | 38.49 | 36.35 | 18.4° |
| 2 | 74.82 | 70.66 | 15.1° |
| 3 | 109.11 | 103.05 | 12.0° |
| 4 | 141.48 | 133.62 | 9.2° |
| 5 | 172.03 | 162.47 | 6.6° |
| 6 | 200.87 | 189.71 | 4.2° |
| 7 | 228.08 | 215.41 | 2.0° |
| 8 | 253.77 | 239.67 | 0.0° |
| 9 | 278.02 | 262.58 | -1.8° |
| 10 | 300.91 | 284.19 | -3.5° |
| 11 | 322.51 | 304.59 | -5.0° |
| 12 | 342.90 | 323.85 | -6.5° |
| 13 | 362.15 | 342.03 | -7.8° |
| 14 | 380.31 | 359.18 | -8.9° |
| 15 | 397.46 | 375.38 | -10.0° |
| 16 | 413.64 | 390.66 | -11.0° |
| 17 | 428.92 | 405.09 | -12.0° |
| 18 | 443.33 | 418.70 | -12.8° |
| 19 | 456.94 | 431.56 | -13.6° |
| 20 | 469.79 | 443.69 | -14.3° |
| 21 | 481.91 | 455.14 | -15.0° |
| 22 | 493.35 | 465.95 | -15.6° |
| 23 | 504.16 | 476.15 | -16.2° |
| 24 | 514.35 | 485.78 | -16.7° |
How to use it
- Tap a preset (6, 7 or 8 strings, 5-string bass) or type the scales, in inches or millimeters.
- Choose the perpendicular fret. At 0, the nut is square and the whole fan goes to the bridge; at the 7th or 8th, the fan is split between both ends.
- Enter the distance between the outer strings, center to center, at the nut and at the bridge.
- Print the template at 100%, measure the 100 mm bar and join the sheets on the gray strip.
Help and explanations
Enter the bass and treble scale lengths, the number of strings and frets, the perpendicular fret and the center-to-center distance between the outer strings at the nut and at the bridge. The calculator gives the position and angle of every fret and builds a full-size template.
How the geometry works
The math is the same as FretFind2D by A. Spike: each string is a straight line from nut to bridge, and the scale of the inner strings is interpolated between the bass and treble sides. On each string, fret n sits at L − L ÷ 2^(n/12) from the nut, and the perpendicular fret lines up across all of them. The points of one fret fall on a straight line, so every fret is still a straight piece of wire, slotted at the angle in the table.
Common scale pairs
On 6- and 7-string guitars the most common pair is 25.5″ on the treble side and 27″ on the bass side (647.7 to 685.8 mm). Eight-strings often go to 28″ (711.2 mm) on the low string. Basses run 35″ to 37″ on the low side, with 34″ or 35″ on the high side.
On the 6-string preset with the 8th fret perpendicular, the 1st fret slants about 18° and the 24th about 17° the other way; the low-string saddle sits 24 mm (just under 1″) farther back than the high-string saddle.
Choosing the perpendicular fret
Put the perpendicular fret where your hand spends most of its time and the angles stay small there. A square nut (fret 0) is simpler to build, but the fan grows toward the body: on a 25.5″–27″ neck, the 24th fret passes 30°. Many builders settle on the 7th or 8th as a compromise.
Tips
- A longer bass-side scale lets you use a lighter gauge for the same tuning; check it in the string tension calculator.
- Once it's built, set the intonation of each string with the intonation checker.
- Tape the template flat to the board and check each fret line against the outer-string marks before you saw.
Frequently asked questions
What is a multiscale or fanned fret guitar?
A neck where each string has a different scale length and the frets fan out. A typical 6-string uses 25.5″ (647.7 mm) on the high E and 27″ (685.8 mm) on the low E, 1.5″ (38.1 mm) longer.
Which fret should be perpendicular?
Most builders pick between the 7th and 9th. With the 8th perpendicular on a 25.5″–27″ fan, the 1st fret sits at about 18° and the 24th at about 17°. With a square nut, the 24th goes past 30°.
What scale length for an 8-string guitar?
The most common pairs are 25.5″–27″ and 25.5″–28″ (647.7 to 711.2 mm). The 28″ side gives the lowest string more tension without a very heavy gauge.
What about a multiscale bass?
On a 5-string bass, the low side is usually 35″ to 37″, with 34″ to 35″ on the high side. The preset uses 37″ (939.8 mm) and 34″ (863.6 mm), with the 7th fret perpendicular.
Does the template print at full size?
Yes, when printed at 100%. Each sheet has a 100 mm bar to check with a ruler, and long necks print across several sheets.