Advanced Fret Distance Calculator

Calculator Inputs

Enter your scale and fret settings below. After pressing calculate, the results appear above this form and below the header.

Instrument Name

Scale Length

Unit

Total Frets

Divisions per Octave

Bridge Compensation

Open-String Frequency (Hz)

Decimal Precision

Example Data Table

Illustrative sample for a 25.5-inch scale, 12 divisions per octave, and standard equal-tempered fret placement.

Fret	Nut to Fret (in)	Interval (in)	Remaining String (in)
1	1.431	1.431	24.069
2	2.782	1.351	22.718
3	4.057	1.275	21.443
5	6.397	1.136	19.103
7	8.481	1.012	17.019
12	12.750	0.758	12.750

Formula Used

This calculator models fret placement with equal temperament. The pitch ratio between neighboring frets is r = 2^(1 / d), where d is the number of divisions per octave.

The position of fret n from the nut is: xₙ = L × (1 - 2^(-n / d))

Here, L is the effective scale length, which equals: effective scale = scale length + bridge compensation

The remaining vibrating string after fret n is: L / 2^(n / d)

For 12-tone fretboards, the familiar workshop constant becomes: 1 / (2^(1/12) - 1) ≈ 17.817

How to Use This Calculator

Enter a name for your instrument or project.
Type the scale length in inches or millimeters.
Choose how many frets you want to calculate.
Set divisions per octave. Use 12 for standard guitar-style equal temperament.
Add bridge compensation if your effective vibrating length needs a small extension.
Enter an open-string frequency if you want frequency values shown for every fret.
Select display precision, then press Calculate Fret Distances.
Review the summary cards, graph, detailed table, and export the layout to CSV or PDF.

Frequently Asked Questions

1) What does this fret distance calculator measure?

It calculates each fret’s position from the nut, the spacing between adjacent frets, the remaining vibrating string length, and the related pitch ratio. It also estimates fret frequencies from the open-string frequency you enter.

2) Why is the 12th fret so important?

On a standard 12-division layout, the 12th fret marks one octave above the open string. That puts it at half the effective vibrating length, making it a practical reference for fretboard checks, bridge setup, and intonation work.

3) What is the 17.817 constant?

It is the common fret-spacing constant for 12-tone equal temperament. Builders use it as a convenient shortcut because each new fret distance can be derived from the remaining scale length divided by about 17.817.

4) Can I use inches and millimeters?

Yes. Choose the unit that matches your drawing, ruler, or workshop process. The calculator keeps every result in the same unit you selected, so your output table, graph, CSV, and PDF remain consistent.

5) Why would I add bridge compensation?

Bridge compensation lets you model a slightly longer effective scale length. This is useful when setup decisions or design allowances shift the final vibrating length a little beyond the nominal scale measurement.

6) Does this work for basses, mandolins, and custom builds?

Yes. The math depends on scale length and temperament, not the instrument label. You can use it for guitars, basses, mandolins, ukuleles, experimental instruments, or any project that needs equal-tempered fret spacing.

7) What changes when I alter divisions per octave?

Changing divisions per octave changes the pitch ratio between frets and therefore the physical spacing. Use 12 for mainstream fretted instruments, or other values when exploring alternate equal-tempered systems and custom acoustic experiments.

8) Why do fret gaps shrink toward the bridge?

Each fret shortens the remaining vibrating string by the same ratio, not the same absolute distance. Because the remaining length keeps getting smaller, each next fret interval also becomes physically smaller toward the bridge.