Fret Calculator

A Fret Calculator is used by luthiers, guitar makers, and musicians to determine the precise placement of frets on a stringed instrument’s neck.

Frets are the metal strips on the neck of guitars, bass guitars, and similar instruments that divide the neck into fixed segments of musical intervals.

When building a guitar with a scale length (the distance from the nut to the bridge) of 25.5 inches, a Fret Calculator would help you determine that the first fret should be placed 1.431 inches from the nut.

Fret Calculation Chart

Fret Calculation Formula

The formula for calculating fret positions is based on the concept of equal temperament and uses the “Rule of 18”:

Distance from nut = Scale Length - (Scale Length / (2^(n/12)))

Where:

• Scale Length is the distance from the nut to the bridge
• n is the fret number

For example, let’s calculate the position of the 5th fret on a guitar with a 25.5-inch scale length:

Distance = 25.5 – (25.5 / (2^(5/12)))
= 25.5 – (25.5 / 1.3348398541700344)
= 25.5 – 19.116
= 6.384 inches

This means the 5th fret should be placed 6.384 inches from the nut.

How do you calculate frets?

Here’s a step-by-step example for finding the first three fret positions on a bass guitar with a 34-inch scale length:

Determine the scale length (34 inches in this case)

Apply the formula for each fret: For the 1st fret:

34 - (34 / (2^(1/12))) = 34 - 32.108 = 1.892 inches For the 2nd fret:
34 - (34 / (2^(2/12))) = 34 - 30.306 = 3.694 inches For the 3rd fret:
34 - (34 / (2^(3/12))) = 34 - 28.593 = 5.407 inches

These calculations give you the distance from the nut to each fret. Luthiers use these measurements to precisely place frets, ensuring accurate intonation across the instrument’s range.

The process continues for all frets, typically up to the 22nd or 24th fret on most guitars and basses.

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