Free calculators for guitar building, and a winder you can print

Why these tools

I like music and guitars, building them as much as playing them. I also do a fair amount of DIY, electronics, 3D printing and CAD design, and I spend time on boats, planes and RC.

I needed these calculators for my own projects, so I wrote them. They are here, free and with no sign-up.

The fret calculator gives the position of every fret from your scale length, the neck width at each position, and a table you can print. It works on guitar, bass, ukulele, banjo, mandolin or a cigar box guitar, handles multiscale necks, prints a full size template at home, and exports a DXF or SVG file for CAD. The pickup winding calculator starts from your core dimensions, wire gauge and target resistance to estimate turns, wire length and inductance. It also builds the matching bobbin former from those same dimensions and exports it as a 3D file you can print, rather than handing you a fixed model. Around eighty known pickups are included as reference points.

The string tension calculator completes the other two: it gives the pull of every string from your tuning and scale length, and works the other way round as well, suggesting the gauges that reach a tension you choose.

The radius sanding block is the second part the site builds instead of calculating: pick the radius you want on your fretboard and it writes the block to print, in STEP and in STL, on the length and the width you ask for.

The coil winder is the last one, and the only one that needs a machine: it turns those same core dimensions and a turn count into a winding plan, layer by layer, and into the file my CNC winder runs.