Guitar Fret Distance Calculator
Calculates the exact distance from the nut to each fret on a guitar, accounting for string gauge and compensation. Essential for luthiers and DIY builders laying out a new fretboard accurately.
About this calculator
Fret placement follows equal temperament: each semitone divides the octave into 12 equal ratio steps, so each fret is placed at a fraction of the remaining string length. The core formula is: fretDistance = scaleLength × (1 − 2^(−fretNumber/12)) × compensationFactor × (1 + stringGauge/100). The term 2^(−n/12) comes from the twelfth root of two, which defines equal-tempered tuning. The compensation factor adjusts for bridge saddle offset, which corrects intonation caused by string stiffness. String gauge also shifts the effective vibrating length slightly, which is why heavier strings need more compensation. Together these factors ensure every fret plays in tune across the entire neck.
How to use
Suppose you're building a guitar with a 25.5-inch scale length, placing fret 12, using a compensation factor of 1.0, and standard 10-gauge strings (stringGauge = 10). Calculation: 25.5 × (1 − 2^(−12/12)) × 1.0 × (1 + 10/100) = 25.5 × (1 − 0.5) × 1.0 × 1.1 = 25.5 × 0.5 × 1.1 = 14.025 inches. So the 12th fret sits 14.025 inches from the nut. This is just over half the scale length, confirming the octave relationship, with a small upward correction for string gauge.
Frequently asked questions
What scale length should I use for a standard electric guitar fret calculator?
Most standard electric guitars use a scale length of 25.5 inches (Fender style) or 24.75 inches (Gibson style). The scale length is measured from the nut to the saddle. Choosing the correct scale length is the single most important input because every fret position is derived from it proportionally. Even a small error in scale length will cause cumulative intonation problems up the neck.
Why does string gauge affect fret placement in a guitar fret distance calculator?
Heavier strings have greater stiffness and tension, which slightly increases their effective vibrating length beyond the physical nut-to-saddle distance. This phenomenon, called inharmonicity, means the string acts as if it is marginally longer than measured. The stringGauge term in the formula (1 + stringGauge/100) applies a small upward correction to account for this. In practice the effect is small but noticeable for wound bass strings or very heavy gauges.
What is the compensation factor in a guitar fret position calculator?
The compensation factor adjusts for bridge saddle setback, a deliberate offset that corrects intonation errors caused by fretting action and string elasticity. A value of 1.0 means no compensation is applied, which is fine for a theoretical layout. Real instruments typically require saddle compensation of 1–3 mm depending on string type and action height. Luthiers fine-tune this value by measuring intonation at the 12th fret and adjusting the saddle position until the fretted note matches the harmonic.