Equal Temperament Fret Calculator
Use this tool to calculate fret positions for guitar, bass, ukulele, or custom stringed instruments. Enter your scale length and fret count, then generate accurate measurements from the nut.
Formula used: Distance from nut to fret n = Scale Length − (Scale Length / 2^(n/12))
What a Fret Calculator Does
A fret calculator converts your chosen scale length into precise fret locations based on the 12-tone equal temperament system. In practical terms, this gives you the exact distance from the nut to each fret so your instrument plays in tune across the fingerboard.
Whether you are building from scratch, modifying an existing neck, or checking CNC/laser templates, accurate fret layout is one of the most important steps in instrument construction.
How the Math Works
The equal temperament rule
Each semitone shortens the vibrating string length by a factor of the twelfth root of 2. That means every fret is placed according to an exponential relationship—not a linear one.
For fret number n:
- Distance from nut = L − (L / 2^(n/12))
- Distance from previous fret = current fret distance − previous fret distance
- Remaining string length = L − distance from nut
At fret 12, the remaining string length is exactly half the scale length (in an ideal equal-tempered layout).
How to Use This Tool
- Enter your target scale length (for example: 25.5 in, 24.75 in, 648 mm, 635 mm).
- Choose the number of frets you want to lay out.
- Select inches or millimeters.
- Click Calculate Frets to generate the full table.
The output table is organized for workshop use: each row shows fret number, location from nut, spacing from the previous fret, and the remaining speaking length.
Practical Build Tips
1) Mark from one reference point
Always mark fret positions from the same nut reference edge. Chaining measurements from fret to fret can compound tiny errors.
2) Use fine tools for layout
A precise rule, sharp marking knife, and good lighting can make a dramatic difference. If possible, verify marks with digital calipers before slotting.
3) Consider kerf and saw setup
Fret slot width should match your fret tang and press/hammer method. Consistent slot depth and width help fret seating and long-term stability.
4) Leave room for compensation
This calculator provides theoretical equal-tempered positions. Final intonation is adjusted at the bridge and influenced by action height, string gauge, and playing pressure.
Common Scale Length Examples
- 25.5 in (647.7 mm) – Common Fender-style guitar scale
- 24.75 in (628.7 mm) – Common Gibson-style guitar scale
- 34 in (863.6 mm) – Common electric bass scale
- 23 in to 26 in – Common ukulele and baritone variants
Final Thoughts
A reliable fret calculator saves time, reduces mistakes, and helps you produce instruments that intonate cleanly up the neck. Use this as your starting point, then combine it with strong workshop technique and careful setup for best results.