Fret Calculator
Calculate guitar fret positions and spacing using the rule of 18 and scale length for luthiers and players.
What Is Fret Spacing?
Fret spacing is the distance between frets along a guitar fingerboard. Each fret shortens the vibrating string length by one semitone, so positions follow a logarithmic pattern rather than equal spacing.
The Fret Placement Formula
Distance from the nut for fret n equals scale length times (1 minus 1 divided by 2 raised to n/12). The constant 2^(1/12) comes from the Western chromatic scale, where each half step multiplies frequency by that ratio.
A standard electric guitar often uses a 25.5 inch scale length. The 12th fret sits exactly at the midpoint, one octave above the open string.
Related tools: Chord Calculator, Chord Finder, and BPM Calculator.
Frequently Asked Questions
What scale length should I use?
Fender-style guitars commonly use 25.5 inches. Gibson-style guitars often use 24.75 inches. Bass guitars typically range from 30 to 34 inches.
Why are frets closer together near the body?
Each fret must shorten the string by the same musical interval. Because the remaining string gets shorter, the physical distance between frets shrinks toward the bridge.
What is the rule of 18?
It is a quick approximation: divide the scale length by 18 repeatedly to estimate fret positions. The exact formula uses 2^(1/12) for precise semitone spacing.
Where is the 12th fret on a 25.5 inch scale?
At 12.75 inches from the nut, exactly half the scale length. That point produces a note one octave above the open string.
Can this calculator work for ukulele or bass?
Yes. Enter the instrument scale length in inches, centimeters, or millimeters. The same chromatic formula applies to any Western fretted string instrument.
Related Tools
Powers of i Calculator
BAC Calculator
Date Calculator
Reverse Integer Digits
Latitude Longitude Distance
Fertility By Age Calculator
Weibull Distribution Calculator
Inches to CM Converter
Ceiling Function Calculator
Analyze JSON
Covariance Calculator
MurmurHash3 Generator
AAA Triangle Calculator
Voltage Converter
Natural Log
Osteoporosis Risk Score Calculator
CSV to TSV Converter
Circle Arc Calculator
Age In Months Calculator
Humans Vs Vampires