Wire gauge converter
Turn an AWG number into real dimensions: 12 AWG, the usual branch-circuit copper, measures 2.052525388494 mm across. You get diameter in mm, inches and mils and area in mm², square inches and circular mils, from 4/0 up to 40. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- American Wire Gauge
- 12
- Awg
- 12
- Awg label
- 12 AWG
- Diameter mm
- 2.0525253885
- Diameter in
- 0.0808080862
A wire gauge converter turns an American Wire Gauge number into the solid-conductor dimensions electricians and designers actually need. Larger AWG numbers mean thinner wire: twelve AWG is common building branch-circuit copper, twenty-two AWG is hookup wire, and four-ought is heavy feeder stock.
What American Wire Gauge means and how diameter is defined
American Wire Gauge is a logarithmic solid-conductor sizing system used across North American electrical work, electronics, and many international product sheets that still quote AWG. The defining geometric relation for solid round copper or aluminum conductors is the closed formula diameter in millimetres equals zero point one two seven times ninety-two raised to the power of thirty-six minus n divided by thirty-nine, where n is the gauge number. That expression is continuous, so half gauges such as twelve point five are well-defined even when stock charts list only integers.
Non-positive gauges use aught notation: zero AWG is one-ought (1/0), minus one is two-ought (2/0 or 00), minus two is three-ought (000), and minus three is four-ought (0000). Cross-sectional area follows from elementary geometry: area equals pi times radius squared, or equivalently pi times diameter squared over four. In US electrical practice area is often quoted in circular mils, the square of the diameter expressed in thousandths of an inch, which avoids pi when comparing relative ampacity tables.
This tool reports all three diameter units and all three area units so you can paste the field that matches your drawing, spreadsheet, or code. It does not adjust for stranded constructions, plating, insulation outer diameter, or temperature-dependent expansion; those are product-specific and belong in manufacturer data sheets after you know the solid AWG equivalent size.
Practical tips, limits, and related searches
Keep gauges inside the published inclusive band from minus three through forty so results stay within the same solid-wire table used by sibling electrical tools in this catalog. Remember that larger AWG numbers are thinner: twenty-four AWG is much finer than ten AWG, and confusing that direction is a common homework and panel-schedule error. When you need voltage drop along a run, use a dedicated voltage-drop calculator that already embeds this diameter map rather than re-deriving resistance by hand from the area fields here.
Stranded cables of a given AWG have slightly different outer geometry and fill factor than solid; treat these results as the solid reference diameter and area, then apply manufacturer stranding factors if your code requires them.
What you can do with it
Panel schedule and drawing notes
Convert branch-circuit AWG labels into mm diameter and mm² area for mixed SI/imperial drawings and bill-of-materials exports.
FAQ
What AWG range does this converter support?
Gauges from −3 (0000 / 4/0 AWG) through 40 inclusive.
Does a larger AWG number mean thicker wire?
No. Larger AWG numbers are thinner. 22 AWG is finer than 12 AWG; 4/0 is much thicker than 10 AWG.
Is this for solid or stranded wire?
Results are solid-conductor reference diameter and geometric area. Stranded cables may differ slightly; use manufacturer data for stranding factors.
Is the wire gauge converter free?
The browser tool is free and runs locally.
What do 1/0, 2/0, 3/0 and 4/0 mean?
They are the aught sizes for gauges at zero and below. 0 AWG is 1/0, −1 is 2/0, −2 is 3/0 and −3 is 4/0, also written 0000, the heaviest size the converter covers.
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/conv/wire-gauge \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"gauge":12}'const res = await fetch("https://api.kit.forhosting.com/conv/wire-gauge", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"gauge": 12
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/wire-gauge",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"gauge": 12
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/wire-gauge", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"gauge":12}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"gauge":12}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/wire-gauge", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"gauge": 12
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.wire_gauge",
"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.
Limits
gauge_min | -3 |
gauge_max | 40 |
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
Enter an AWG size from 0000 (4/0, gauge −3) through 40; the tool returns diameter in millimetres, inches, and mils, plus cross-sectional area in square millimetres, square inches, and circular mils using the standard closed formula d_mm equals 0.127 times 92 to the power of (36 minus n) over 39. Out-of-range gauges are rejected with a clear invalid_input error so automation never invents a phantom diameter.
How to call the API and what comes back
String forms are accepted when they match a finite numeric pattern or common aught spellings such as four-slash-zero, 0000, or twelve AWG after trimming. Prefer numeric gauge when you control the client; reserve string aught forms for forms that accept human-typed labels. Send a JSON body with one required finite number named gauge (aliases awg, wire_gauge, size, n, and awg_gauge). Absolute gauge values must fall between minus three and forty inclusive; values outside that band raise invalid_input and are never charged. On success the response echoes rounded gauge and awg, sets awg_label to a human-readable tag including aught forms when applicable, diameter_mm, diameter_in, and diameter_mils for linear size, area_mm2, area_in2, and area_circular_mils for section, gauge_min and gauge_max for the published band, formula to the diameter and area expressions, message to a one-line English summary, and steps to an ordered array of substitution lines you can assert in tests. Failed validation—missing gauge, non-finite values, unparseable strings, or out-of-range gauges—returns invalid_input. Pricing is a flat $0.002 per successful request with unit item and zero marginal unit price.
Practical tips, limits, and related searches
When you need resistance from resistivity, length, and area, feed area_mm2 or area_in2 into a resistivity tool; this landing only answers size geometry. Round-trip checks are easy: recompute zero point one two seven times ninety-two to the power of thirty-six minus n over thirty-nine by hand for a known chart row such as twelve AWG and confirm diameter_mm matches within the published rounding. This landing targets people searching for a wire gauge converter, AWG to millimetres, AWG to inches, or circular mils from gauge; it is not a British SWG converter, not an ampacity table, and not a voltage-drop engine. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when you deliberately probe the range edges.
Integration use cases
Firmware and fixture design
Map hookup-wire AWG to mils and circular mils when specifying PCB-to-chassis harness stock and connector barrel sizes.
Unit tests for electrical libraries
Generate known-good AWG diameter and area fixtures plus deliberate out-of-range rejections for catalog and CAD converters.
Technical questions
How is diameter calculated from AWG?
Using the standard solid-conductor formula d_mm = 0.127 × 92^((36 − n) / 39), then d_in = d_mm / 25.4.