Convert AWG to wire diameter in mm and cross-section area in mm². Covers AWG 40 (thinnest, 0.079 mm) through 4/0 (thickest, 11.684 mm). Geometry only.
Inputs
American Wire Gauge number. Positive for standard gauges (1–40), zero for 1/0, negative for larger sizes: −1 = 2/0 (00), −2 = 3/0 (000), −3 = 4/0 (0000).
Results
Enter a value to see results.
Wire conductor diameter computed from the AWG geometric formula (ASTM B258).
Circular cross-section area of the conductor: A = π/4 × d².
The AWG system
AWG (American Wire Gauge) is a standardized logarithmic wire sizing system first published in the United States and later codified in ASTM B258. It is the dominant gauge system for copper and aluminium electrical conductors in North America and is widely referenced worldwide for electronics, networking, and appliance wiring.
The AWG scale runs inversely to physical size: a higher gauge number corresponds to a thinner wire. AWG 40 is among the finest wires commercially produced (0.079 mm diameter); AWG 4/0 (written 0000 or −3 in numeric form) is a heavy power conductor at 11.684 mm diameter.
The AWG geometric formula
The AWG system is defined by a single closed-form expression. For a gauge number :
Two anchor points pin the scale:
Gauge
Diameter
AWG 36
0.127 mm (exact)
AWG 0
8.251 mm
Between these anchors, every 6 gauge steps halves the cross-section area (roughly), and every 3 steps halves the diameter. The ratio 92:1 spans the 39 steps from AWG 36 down to AWG −3 (4/0).
Cross-section area is derived geometrically from the diameter:
The 0, 00, 000, 0000 (aught) sizes
Gauges larger than AWG 1 are written with zeros read as "aught": AWG 1/0 (one-aught), 2/0, 3/0, and 4/0. This calculator uses numeric equivalents to avoid ambiguous entry:
Numeric entry
Traditional notation
Common name
0
1/0
"one-aught"
−1
2/0
"two-aught" (00)
−2
3/0
"three-aught" (000)
−3
4/0
"four-aught" (0000)
Reference table for common gauges
AWG
Diameter (mm)
Area (mm²)
Typical application
40
0.079
0.0049
Fine magnet wire, precision sensors
28
0.321
0.081
USB, ribbon cables
24
0.511
0.205
Ethernet (Cat 5/6), telephone
22
0.644
0.326
Doorbell, low-voltage control
18
1.024
0.823
Extension cords, speaker wire
14
1.628
2.081
Residential branch circuits
12
2.053
3.309
Residential branch circuits
10
2.588
5.261
Appliance and range circuits
6
4.115
13.30
Sub-panels, EV charger feeds
0 (1/0)
8.251
53.48
Service entrance conductors
−3 (4/0)
11.684
107.2
Heavy feeders, large motors
Metric equivalents and IEC cross-section codes
Outside North America, conductor size is specified directly by cross-section area in mm² — a value this calculator computes from AWG. Common IEC equivalents:
AWG
Approximate IEC mm²
14
2.5 mm²
12
4 mm²
10
6 mm²
8
10 mm²
6
16 mm²
These are commercial approximations; exact AWG areas do not coincide with IEC preferred values.
What this calculator does not cover
Ampacity (current-carrying capacity) depends on conductor material, insulation type, ambient temperature, conduit fill, and installation method — factors specific to each jurisdiction's electrical code (NEC, IEC 60364, BS 7671, etc.). This calculator provides geometry only. Always consult the applicable electrical code or a licensed electrician for safe conductor sizing.
Frequently Asked Questions (FAQ)
What is AWG (American Wire Gauge)?
AWG (American Wire Gauge) is a standardized wire gauge system used in North America, defined in ASTM B258. The gauge number runs inversely to wire size: a higher AWG number means a thinner wire. AWG 40 is the thinnest (0.079 mm diameter); AWG 0000 (or 4/0) is one of the thickest common gauges (11.68 mm diameter).
How is the AWG diameter calculated?
The AWG geometric formula is d(mm) = 0.127 × 92^((36 − n) / 39), where n is the AWG number. This formula places AWG 36 at exactly 0.127 mm and AWG 0 at approximately 8.251 mm, with 39 gauge steps spanning a 92:1 diameter ratio. Cross-section area follows from A = π/4 × d².
What AWG sizes are commonly used?
Residential branch-circuit wiring commonly uses AWG 14 (1.628 mm diameter) and AWG 12 (2.053 mm). Electronics and signal wiring ranges from AWG 22 to 28. Heavy power cables use AWG 4/0 (0000, 11.684 mm) and below. AWG 40 (0.079 mm) appears in fine magnet wire and precision sensors. Conductor sizing for current-carrying capacity must follow the applicable electrical code.
What do the negative AWG numbers mean?
AWG sizes larger than 0 are written as 1/0 (pronounced "one-aught"), 2/0, 3/0, and 4/0. This calculator uses numeric equivalents for easy entry: 0 = 1/0 (AWG #0), −1 = 2/0 (AWG #00), −2 = 3/0 (AWG #000), −3 = 4/0 (AWG #0000). The largest standard copper conductor under this system, 4/0 (AWG −3), has a diameter of 11.684 mm.
