Fret Position Calculator – Fret Distances for Any Scale Length

Enter a scale length and see exactly where every fret goes, measured from the nut, from the bridge, and from the previous fret. Works in inches or millimetres.

How fret positions are calculated

In equal temperament each fret raises the pitch by one semitone, which shortens the vibrating string by a constant factor of 2^1/12 (about 1.0595). The distance from the nut to fret n on a scale length L is:

distance from nut = L × (1 − 2^−n/12)

The 12th fret always lands at exactly half the scale length, so a 25.5" scale puts it at 12.75". The first fret on that same scale is 1.431" (36.35 mm) from the nut, and on a 24.75" scale it is 1.389".

Reading the table

From nut is the number to mark along the fingerboard, measured from the nut end.
From bridge is the remaining vibrating length at each fret.
From previous fret is the gap between neighbouring frets, handy for checking a slotting template.

Common scale lengths

Typical values are 25.5" (long-scale electrics and steel-string acoustics), 24.75" (short-scale electrics), 25" (a common in-between electric length), 650 mm (classical), 34" and 30" for long and short scale bass, 13", 15", 17" and 19" for soprano, concert, tenor and baritone ukulele, and 13.875" for mandolin. Measure your own instrument's scale length as twice the distance from the nut to the 12th fret, ignoring saddle compensation.

Limits

This calculator handles single-scale necks. Fanned-fret (multi-scale) layouts are not supported yet. Fret positions locate the fret slots only. Saddle placement is a separate calculation, see the bridge compensation calculator.

Frequently asked questions

What is scale length?

Scale length is the vibrating length of the open string, from the nut to the saddle in theory. In practice you measure it as twice the distance from the nut to the 12th fret, because the saddle is moved back slightly for compensation.

Why is the 12th fret at half the scale length?

The 12th fret raises the pitch by exactly one octave, which means half the vibrating string length. That is why the formula gives L/2 at n = 12.

Does this include bridge compensation?

No. The table gives ideal fret positions. Compensation moves the saddle back, not the frets, and is calculated separately.