Fret Spacing Calculator — Precision Position Chart | LuthierCalc

Calculate exact fret positions for any scale length. Support for guitar, bass, ukulele, and mandolin. Generate a printable fret distance table for your build.

How to Use the Fret Spacing Calculator

Enter the target scale length (the distance from the nut to the bridge saddle). Standard is 25.5" for Fender or 24.75" for Gibson.

Select the number of frets you wish to calculate. The tool provides measurements from both the nut and from fret-to-fret.

Accuracy to the hundredth of a millimeter is required for professional work. Use a digital caliper for marking the first 12 frets.

Frequently Asked Questions

Where do I measure the scale length from?

Measure from the edge of the nut (where it meets the fingerboard) to the center of the bridge saddle adjustment range.

Can I use this for multi-scale (fanned fret) guitars?

Yes. You simply run the calculation twice: once for the shortest scale (treble side) and once for the longest scale (bass side).

How accurate do fret slots need to be?

Ideally within +/- 0.1mm. Errors larger than this will cause noticeable intonation problems that cannot be corrected at the bridge.

What formula does the calculator use?

It applies the twelve-tone equal temperament rule: distance from nut = scale − scale ÷ 2^(n/12). Each fret shortens the remaining vibrating length by the twelfth root of two (about 1.05946), which is the same ratio you sometimes see written as the 'Rule of 17.817'. On a 25.5" (647.7 mm) scale the first fret lands 36.35 mm from the nut and the second 70.66 mm, a gap of 34.31 mm between them.

Where does the 12th fret fall?

At exactly half the scale length, because 2^(12/12) equals 2. On a 647.7 mm scale that is 323.85 mm from the nut; on a 24.75" (628.65 mm) Gibson scale it is 314.32 mm. The 24th fret reaches three-quarters of the scale, 485.78 mm on the Fender scale — a useful check when you mark a board by hand.

Which scale lengths are supported?

Anything you enter, plus presets for the common builds: 24.75" (628.65 mm) and 25" (635 mm), the 25.5" (647.7 mm) Fender scale, classical 25.6" (650 mm), baritone 28.5" (723.9 mm), and 30" (762 mm) and 34" (863.6 mm) bass scales. The fret count accepts 1 to 36 frets, covering guitars, basses, ukuleles and mandolins.