Distance between adjacent frets calculator
On a 25.5-inch scale, the gap from the nut to the first fret is 1.431205026617 inches. Enter your scale length and the fret pair to mark a fretboard blank, set a saw or check a slot with calipers. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Scale length
- 25.5
- From fret
- 0
- To fret
- 1
- Spacing
- 1.4312050266
- Distance
- 1.4312050266
- Distance from nut to from
- 0
A distance between adjacent frets calculator turns a fretted instrument scale length and two consecutive fret numbers into the exact gap you mark on a fretboard blank, CNC path, or layout spreadsheet. Luthiers and DIY builders rarely want only the nut-to-fret distance; they need the short interval from one fret slot to the next so a saw, fretting jig, or digital caliper can check the cut before glue-up. Enter the scale length in inches or millimetres, the lower fret of the pair (zero for the nut), and optionally the upper fret; the tool returns spacing in the same unit, nut-to-fret distances for both ends of the gap, a twelve-tone equal-temperament formula, and ordered steps you can recompute by hand.
How scale length and frets become adjacent spacing
Scale length is the vibrating string length from the nut face to the saddle or bridge contact point when the string is open. Under twelve-tone equal temperament, each fretted half-step multiplies the remaining speaking length by the twelfth root of one half, so the distance from the nut to fret number k is L times one minus two to the power of minus k over twelve.
The gap between two frets is simply the difference of those two nut distances: spacing equals L times the quantity two to the minus lower-fret over twelve minus two to the minus upper-fret over twelve. When frets are adjacent, the upper index is one more than the lower, which is the usual case when you slot a board from the nut outward.
Fret zero means the nut itself, so the first physical metal fret is fret one and the first gap is the nut-to-first-fret distance—the widest gap on a conventional parallel-fret board. Because the remaining string shortens geometrically toward the saddle, successive gaps shrink; a Fender-style twenty-five-point-five inch scale yields roughly one-point-four-three inches from nut to first fret and progressively smaller steps higher up. Rejecting a non-positive scale length is essential: a zero or negative L would invent non-physical slots.
Requiring integer frets and enforcing adjacency keeps this landing focused on the search intent for distance between adjacent frets rather than an arbitrary multi-fret span calculator.
Practical tips, limits, and related searches
Pick one unit and keep it for the whole job: inches of scale length produce inches of spacing; millimetres produce millimetres. Common reference scales include twenty-five-point-five inches for many electric guitars, twenty-four-point-seven-five for many Gibson-style guitars, thirty-four inches for bass, and six hundred fifty millimetres for classical. Prefer this capability when you already know the scale and only need one consecutive gap; if you need every nut-to-fret mark for a twenty-two or twenty-four fret board, generate each adjacent pair in a loop or use a dedicated full-layout tool.
Round-trip checks are straightforward: recompute L times two to the minus n over twelve minus two to the minus m over twelve and confirm it equals spacing within twelve-decimal rounding.
What you can do with it
Check CNC or laser fret paths
Makers compare CAM-generated adjacent gaps against the equal-temperament formula so a programming offset does not shift an entire upper board.
FAQ
How do you calculate the distance between adjacent frets?
With scale length L and lower fret n (0 = nut), the gap to fret n+1 is L × (2^(−n/12) − 2^(−(n+1)/12)) under twelve-tone equal temperament.
What happens if scale length is zero or negative?
Fret spacing is undefined for a non-positive scale length.
Why is fret zero allowed?
Fret zero means the nut. The first gap on the board is from the nut to the first metal fret, which is the adjacent pair (0, 1).
Can I measure spacing between non-adjacent frets?
Not with this calculator. It rejects pairs that are not consecutive so the page stays focused on adjacent-fret distance. Sum adjacent gaps or use a multi-fret layout tool for wider spans.
Is the distance between adjacent frets calculator free?
The browser tool is free and runs locally.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/hobby/music-fret-spacing \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"scale_length":25.5,"from_fret":0}'const res = await fetch("https://api.kit.forhosting.com/hobby/music-fret-spacing", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"scale_length": 25.5,
"from_fret": 0
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/hobby/music-fret-spacing",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"scale_length": 25.5,
"from_fret": 0
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/hobby/music-fret-spacing", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"scale_length":25.5,"from_fret":0}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"scale_length":25.5,"from_fret":0}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/hobby/music-fret-spacing", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"scale_length": 25.5,
"from_fret": 0
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "hobby.music_fret_spacing",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Non-positive scale lengths, non-integer frets, and non-adjacent pairs are rejected with invalid_input so automation never stores a nonsense gap.
How to call the API and what comes back
Send a JSON body with scale_length as a strictly positive finite number—also accepted under the aliases scale, length, scale_len, and L—and from_fret as a non-negative integer, also accepted as lower_fret, fret, fret_from, or n. Optionally include to_fret, also accepted as upper_fret, fret_to, or m; when omitted it defaults to from_fret plus one so a single lower index is enough for consecutive frets. If to_fret is provided it must equal from_fret plus one; larger spans return invalid_input because this capability is deliberately adjacent-only. Scale length must stay at most one million length units and from_fret at most one hundred so intermediate powers stay finite in IEEE double precision. Missing fields, non-numeric strings, non-finite values, non-integer frets, and out-of-range numbers return invalid_input and are never charged. On success the response echoes rounded scale_length, from_fret, and to_fret; sets spacing and distance to the gap; sets distance_from_nut_to_from and distance_from_nut_to_to; sets temperament to the string twelve-TET; formula to the closed equal-temperament relation; and message to a short English summary. Pricing is a flat $0.002 per successful request with unit item.
Practical tips, limits, and related searches
When teaching, pair a happy path such as nut to first fret on a twenty-five-point-five scale with a deliberate zero scale length or a non-adjacent to_fret to demonstrate the hard invalid_input path. This landing targets people searching for a distance between adjacent frets calculator, fret spacing from scale length, or guitar fretboard gap tool; it is not a full multi-fret position table for every fret at once, not a compensated nut or saddle intonation solver, not a string-gauge tension calculator, and not a multi-scale fanned-fret per-string layout engine. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when learners deliberately probe edge cases.
Integration use cases
Mark a DIY fretboard blank before slotting
Hobby luthiers enter scale length and from_fret zero through the board, read each adjacent spacing, and transfer gaps to a rule or caliper before cutting slots.
Unit tests for instrument layout helpers
Developers feed known scale lengths and fret pairs and assert spacing against golden fixtures without CAD software or wall-clock timers.