MusicReasonPitch, Tuning, Intonation, and Fret Geometry
Where do the frets go on this scale length?
Enter a scale length and fret count. This tool calculates each fret's equal-tempered distance from the nut and bridge, as a starting geometry, not a manufacturing specification.
Answer
Want to learn more? Fretboards, Tunings, Capos, and Sounding Pitch
Understand
This calculator computes the ideal equal-tempered geometry only; it does not account for a real instrument's intonation compensation at the bridge or saddle, which a luthier adjusts empirically after stringing and tuning the instrument. Treat this table as a starting layout, not a finished specification.
Worked example
On a 648 mm (25.5 inch) scale length, the 12th fret sits at exactly 324 mm from the nut, precisely half the scale length, since the 12th fret is one octave above the open string.
Method and limitations
Nut-to-fret distance for fret n is L − L / 2^(n/12), where L is the scale length; bridge-to-fret distance is the remainder. Internal values keep full precision and round only for the displayed table, which is monotonically increasing by construction.
Why compensation is a separate, later step
A string's actual pitch when fretted runs slightly sharp of the ideal calculation, mostly because pressing a string down stretches it very slightly and adds tension. Luthiers correct for this with saddle compensation, moving the effective scale length a small, empirically tuned amount at the bridge, which is exactly why this calculator's output is a starting geometry rather than a finished, ready-to-cut specification.