Multiscale Fretboard Planner

What this tool is for

Generate string lines and per-fret 2D coordinates around a selected perpendicular fret. Geometry tools apply explicit models to named measurements. A coordinate or angle must still be checked against a physical drawing, real hardware, tolerances, and material behavior.

Use it when you can describe the current state and need a defensible next check. It is not a shortcut around inspection: preserve the starting state, change one variable, and verify the result under the same conditions.

Before you begin

Enter treble and bass scales, string count, fret count, perpendicular fret, and measured nut/bridge outer-string spreads. Define which side is treble before marking.

• Use a stable, tuned instrument unless the page specifically investigates tuning.
• Name the physical reference, unit, and test condition beside every important number.
• Keep the original measurements so any reversible change can be returned to baseline.

Input guide

Treble scale

defines speaking length or the geometric reference used by the calculation.

Bass scale

defines speaking length or the geometric reference used by the calculation.

Number of strings

provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.

Number of frets

provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.

Perpendicular fret number

provides a measured or counted input; confirm the allowed range and repeat the reading before relying on it.

Outer-string nut spread

supplies a measured geometric quantity whose datum and resolution should be written down.

Outer-string bridge spread

supplies a measured geometric quantity whose datum and resolution should be written down.

Input and display unit

sets the interpretation and display unit; do not mix units elsewhere in the same run.

Paper size

classifies an observed condition; choose “unknown” or “not tested” instead of guessing when available.

Orientation

classifies an observed condition; choose “unknown” or “not tested” instead of guessing when available.

Input labels describe evidence, not targets. A placeholder demonstrates format only; it is never a recommendation for a particular guitar.

How the result should be read

Inspect coordinate ordering, scale endpoints, and the exact perpendicular fret. Export coordinates into a full drawing that includes neck taper and physical margins.

Read priorities from top to bottom, but stop as soon as new evidence contradicts an earlier assumption. Save or print the result ticket with the entered conditions so another person can reproduce the decision.

Method and logic

Each string receives its own 12-TET distances; nut and bridge endpoints are positioned so the selected fret lies on the chosen perpendicular line, producing 2D fret intersections.

The page keeps calculation and diagnostic claims deliberately bounded. Display rounding improves readability, while the underlying logic uses entered values; descriptive branches report relative tendencies and the evidence needed to confirm them.

Worked example

A seven-string plan with 25-inch treble, 27-inch bass, and fret 8 perpendicular should collapse to ordinary straight frets if both scales are changed to the same value—an important fixture.

The example demonstrates reasoning, not a universal setup specification. Substitute real measurements and repeat the final test before accepting the next action.

Assumptions and limitations

The planner omits fret-slot kerf, nut compensation, bridge compensation, fretboard edge, binding, overhang, structural layout, and ergonomic validation. Do not cut from coordinates alone.

Instrument design, service history, measurement error, and player technique can outweigh a calculator or checklist. Where manufacturer instructions exist for the exact hardware, use those instructions and record the revision consulted.

Safety and stop conditions

Stop for abnormal resistance, cracking, heat, odor, electrical sensation, moving wood or joints, a measurement that cannot be repeated, or any step that would remove material without a confirmed cause. Secure strings and stored mechanical energy before hardware work. Refer structural, fret-cutting, mains-powered, or uncertain repairs to a qualified technician.

Related workflow

• Fret Position Formula — Review the 12-TET coordinate model.
• Geometry Measurement Definitions — Name every datum before entering a number.
• Fret Position Template Generator — Calculate cumulative and adjacent 12-TET fret positions with calibrated print references.

Open the related page that answers the next unresolved question; do not run every tool as if every system needs adjustment.