Guitar Fret Spacing Calculator

Calculate exact fret positions from nut using scale length. Essential for guitar building and luthiery. Supports all common scale lengths from 24.75" to 27" and beyond.

"
Nut to Fret Distance
—
Nut to Fret (mm) —
Fret 12 Check —
Extended More scenarios, charts & detailed breakdown ▾
"
Fret 12 (octave)
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Fret 1 (nut→fret, in) —
Fret 3 —
Fret 5 —
Fret 7 —
Fret 9 —
Fret 15 —
Fret 17 —
Fret 19 —
Fret 24 (2nd octave) —
Professional Full parameters & maximum detail ▾

Fret Measurement

Nut to Fret (inches) —
Nut to Fret (mm) —
This Fret to Next (inches) —

Reference & Verification

Rule of 18 Estimate (inches) —
Fret 12 = Scale / 2 —
Saddle Compensation Note —

How to Use This Calculator

  1. Enter the guitar's Scale Length in inches (Fender = 25.5", Gibson = 24.75").
  2. Enter the Fret Number you want to measure to.
  3. The calculator gives exact nut-to-fret distance in both inches and millimeters.
  4. Use All 24 Frets for a full table, or Fret-to-Fret Spacing for slot cutting measurements.

Formula

Nut to Fret n = Scale Length × (1 − 1 ÷ 2^(n/12))

Where n = fret number. Fret 12 always = Scale Length ÷ 2.

Example

25.5" scale, fret 5: d = 25.5 × (1 − 1/2^(5/12)) = 25.5 × (1 − 0.7491) = 25.5 × 0.2509 = 6.397" from the nut.

Frequently Asked Questions

  • The distance from the nut to fret n = Scale Length × (1 − 1/2^(n/12)). This is based on 12-tone equal temperament where each fret divides the remaining string length by the 12th root of 2.
  • The Rule of 18 (actually 17.817) is a historical approximation: each fret is placed at 1/18th of the remaining string length from the previous fret. It's slightly inaccurate but was used before precise calculators were available.
  • At fret 12, the vibrating string length is halved, which doubles the frequency — exactly one octave higher. This is a fundamental property of equal temperament and serves as a verification point for accurate fret placement.
  • Most guitars need 2–4 mm of saddle compensation to intonate correctly. Wound strings need more compensation than plain strings. The bridge saddle is intentionally set slightly farther than the theoretical scale length to account for string stiffness.

Related Calculators

🎸 Guitar String Tension 🎸 Capo Position Calculator 🎵 Note Frequency Calculator
Sources & References (5) ▾
  1. Fret Calculator and Setup Guide — StewMac
  2. Lutherie: Fret Scale Calculations — Liutaio Mottola Lutherie
  3. Guitar Acoustics and Scale Length — Acoustical Society of America
  4. Fret Placement and Intonation — Frets.com (Frank Ford)
  5. Building the Guitar: Scale Length Reference — Guitar Player Magazine