Fret Calculator

Category: Music
- March 24, 2025
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Calculate fret positions for stringed instruments. This calculator determines the exact spacing of frets based on scale length, fret count, and compensation factors to ensure proper intonation.

Instrument Type

Scale Length

Fret Configuration

Intonation Compensation

Advanced Options

About Fret Calculations

Proper fret placement is crucial for the intonation of stringed instruments. The calculations are based on the mathematical principle of equal temperament, which divides an octave into 12 equal semitones.

Scale Length

The scale length is the vibrating length of a string, measured from the nut to the bridge. It's a fundamental parameter that affects the tone, playability, and feel of the instrument.

  • Common Guitar Scale Lengths: 24.75" (Gibson), 25.5" (Fender)
  • Common Bass Scale Lengths: 30", 32", 34", 35"
Intonation Compensation

In practice, perfect mathematical fret placement may require slight adjustments due to:

  • String Deflection: The height of the strings above the fretboard
  • String Tension: The stiffness and elasticity of the strings
  • String Gauge: Thicker strings may require more compensation
Multi-scale (Fan Fret) Designs

Multi-scale or fan fret instruments use different scale lengths for different strings:

  • Benefits: Improved string tension balance, enhanced ergonomics, clearer bass response
  • Perpendicular Fret: The fret where all scales align at right angles to the centerline

What Is the Fret Calculator?

The Fret Calculator is a tool for luthiers, guitar builders, and musicians to determine the precise positions of frets on stringed instruments like guitars, bass guitars, and custom builds. It helps ensure accurate intonation by calculating the distances from the nut to each fret based on scale length and other optional adjustments.

Fret Placement Formula

Distance = Scale Length × (1 - 1 / (2n/12))

This formula divides the scale length using equal temperament, where each semitone is separated by the twelfth root of 2 (≈1.059463). This ensures each fret is placed at the right position to produce the correct pitch.

How to Use the Fret Calculator

Follow these steps to calculate fret positions for your instrument:

  • Select an instrument type: Choose Guitar, Bass Guitar, or Custom Instrument.
  • Enter scale length: Input the scale length and select the unit (inches, mm, or cm).
  • Enable multi-scale (optional): For fan fret designs, input treble and bass scale lengths and choose the perpendicular fret.
  • Set the number of frets: Choose how many frets you want calculated (up to 36).
  • Adjust for compensation (optional): Enter string action, string gauge, and choose or enter a compensation factor.
  • Choose display options: Set decimal places, output units, and toggle visual aids like fretboard diagrams.
  • Click "Calculate": The tool will generate distances for each fret, including a table, notes, and visual diagram.

Why Use This Calculator?

Building or modifying stringed instruments requires accuracy. Incorrect fret placement leads to poor tuning and intonation. This calculator helps by:

  • Ensuring precise fret spacing based on proven mathematical formulas
  • Supporting both standard and multi-scale instrument designs
  • Offering visualization to preview fret layouts
  • Applying optional compensation to improve real-world playability

Key Features

  • Supports Guitar, Bass Guitar, and Custom Instruments
  • Handles single-scale and multi-scale (fan fret) designs
  • Includes compensation options for string gauge and action height
  • Customizable output with unit and precision control
  • Interactive visualization of fret spacing

Frequently Asked Questions (FAQ)

What is scale length?

The scale length is the vibrating length of the string, measured from the nut to the bridge. It affects tone, tension, and feel.

What does the "fret constant" mean?

The fret constant, typically 1.059463, is the twelfth root of 2. It's used in the formula to evenly divide the octave across the fretboard.

What is intonation compensation?

Compensation adjusts fret positions slightly to account for string height and gauge. This helps improve tuning accuracy, especially higher up the neck.

What is a multi-scale or fan fret design?

A multi-scale instrument uses different scale lengths for each string. This improves string tension balance and playing ergonomics, especially on extended range guitars or basses.

Can I use this for non-standard instruments?

Yes. Select "Custom Instrument" and input your desired parameters. You can customize scale length, fret count, and string details.

How accurate is the calculator?

The calculator uses standard mathematical principles and allows fine control over decimal precision. It's suitable for design and build planning.