Wire Gauge Converter

How to use

1. 1Pick the format you have under Convert from: AWG, Diameter (mm), Area (mm2), Diameter (in), Circular mils, or SWG.
2. 2Type the value. AWG accepts 0, 00, 000, 0000 or 1/0, 2/0, 3/0, 4/0 for sizes larger than AWG 1; SWG accepts 7/0 down to 40.
3. 3Read the converted values panel: nearest whole AWG, diameter in mm and inches, cross section in mm2, circular mils, and the closest SWG point with its diameter difference.
4. 4Check the NEC 310.16 ampacity card when the result lands on a whole AWG, then pick the insulation column (60, 75, or 90 deg C) that matches your conductor type and remember to derate for ambient temperature, conductor count, and continuous loads.
5. 5Scroll the AWG and SWG reference tables for the full ladder. Click any AWG or SWG cell to load that size as the active value.
6. 6Use Copy summary to grab the full multi-line conversion in plain text, or use Copy on a result card to grab a single value.

About this tool

Wire Gauge Converter turns one wire size value into every other representation you might need on the bench, on a job site, or in a spec sheet. Pick a source format (AWG, SWG, diameter in mm, diameter in inches, area in mm2, or area in circular mils), type the value, and the page derives the conductor diameter using the exact American Wire Gauge geometric formula d_mm = 0.127 * 92^((36 - n) / 39), then back-computes the cross-sectional area with A = pi * (d / 2)^2 and the circular-mil area as (d in mils) squared. AWG accepts both 1, 2, 3 style numbering and the 0, 00, 000, 0000 (or 1/0, 2/0, 3/0, 4/0) notation used for sizes larger than AWG 1. SWG (British Standard Wire Gauge, BS 3737:1964) is mapped through the canonical 47-row diameter table for gauges from 7/0 down to 40, with the closest SWG point also shown next to any AWG, mm, mm2, inch, or circular-mil input so cross-region projects translate cleanly. A reference panel uses NEC 2020 Table 310.16 ampacity values for copper conductors at 30 deg C ambient with no more than three current-carrying conductors in a raceway, broken out by 60 deg C insulation (TW, UF), 75 deg C insulation (THW, THWN, USE), and 90 deg C insulation (THHN, THWN-2, XHHW-2). The full AWG ladder from 4/0 down to AWG 30 is rendered in a sortable reference table with diameter, area, ampacity, and the closest SWG match per row; clicking any AWG or SWG cell loads it as the active value so you can flip between sizes without retyping. Useful for electricians sizing a service entrance, makers picking hookup wire for a project, EE students studying conductor physics, audio engineers spec'ing speaker cable runs, EV and solar installers picking between AWG 6 and AWG 4 for a 50 A charger drop, model railroaders going from N-gauge through OO, and anyone who has copied a part number from a European parts catalog written in mm2 and needs the closest AWG to order in the US. Everything runs locally on this device: no value, no spec, and no project detail is uploaded.

Free to use. Works in your browser. No signup, no login.