Wire AWG Chart: Gauge, mm², Ampacity & Resistance Reference

Q: How do I convert AWG to mm²?

The formula is: cross-section (mm²) = 0.012668 × 92^((36-AWG)/19.5). In practice, use the reference table: 14 AWG ≈ 2.08 mm², 12 AWG ≈ 3.31 mm², 10 AWG ≈ 5.26 mm², 8 AWG ≈ 8.37 mm², 6 AWG ≈ 13.3 mm², 4 AWG ≈ 21.2 mm², 2 AWG ≈ 33.6 mm², 1/0 AWG ≈ 53.5 mm², 2/0 AWG ≈ 67.4 mm², 3/0 AWG ≈ 85.0 mm², 4/0 AWG ≈ 107 mm².

Q: What is the largest AWG wire size?

The AWG scale goes up to 4/0 AWG (also written 0000 AWG), which has a cross-section of approximately 107 mm² and is the largest standard AWG size. For conductors larger than 4/0 AWG, the American system switches to kcmil (thousands of circular mils), with standard sizes of 250 kcmil, 300 kcmil, 350 kcmil, 400 kcmil, 500 kcmil, 600 kcmil, 700 kcmil, 750 kcmil, and 1000 kcmil used for service entrance and large feeder applications.

How the AWG System Works

AWG (American Wire Gauge) is a standardized system for wire sizes used primarily in North America. The numbering system runs counterintuitively: a smaller AWG number means a larger wire. This is because the original gauge system was based on the number of drawing dies required to reduce a wire to a given diameter — more draws produced a thinner wire, and each draw added a gauge number.

Key AWG facts:

Every 3 AWG steps approximately halves the cross-sectional area (and resistance)
Every 6 AWG steps approximately doubles the wire diameter
AWG 4/0 (0000) is the largest standard AWG size; above that, sizes are expressed in kcmil (thousands of circular mils)
Below AWG 40, wire becomes "magnet wire" territory used in transformers and motors

Complete AWG Reference Table

Ampacity values below are for copper THHN/THWN-2 wire in conduit, from NEC Table 310.16, 75°C column (the column applicable to most circuit terminations). Derate for ambient temperature above 30°C and for bundling per NEC 310.15. See our full ampacity derating guide for correction factor tables.

AWG	Diameter (mm)	Area (mm²)	Nearest IEC Size	Ampacity Cu @75°C	Resistance (Ω/km)
4/0 (0000)	11.68	107.2	120 mm²	230A	0.161
3/0 (000)	10.40	85.0	95 mm²	200A	0.203
2/0 (00)	9.27	67.4	70 mm²	175A	0.256
1/0 (0)	8.25	53.5	50 mm²	150A	0.323
1	7.35	42.4	35 mm²	130A	0.407
2	6.54	33.6	35 mm²	115A	0.514
3	5.83	26.7	25 mm²	—	0.648
4	5.19	21.2	25 mm²	85A	0.816
6	4.11	13.3	16 mm²	65A	1.30
8	3.26	8.37	10 mm²	50A	2.06
10	2.59	5.26	6 mm²	35A	3.28
12	2.05	3.31	2.5 mm²	25A	5.21
14	1.63	2.08	2.5 mm²	20A	8.29
16	1.29	1.31	1.5 mm²	13A	13.2
18	1.02	0.823	1 mm²	—	21.0
20	0.812	0.518	0.5 mm²	—	33.3
22	0.644	0.326	0.35 mm²	—	52.9

* Ampacity values from NEC Table 310.16, copper, 75°C column, not more than three current-carrying conductors in conduit, 30°C ambient. Derate for other conditions.

AWG vs Metric (IEC) Wire Sizes

Most of the world outside North America uses the IEC metric wire size system, measured directly in mm². The metric system doesn't have the backwards numbering quirk: a larger number is always a larger conductor. When sourcing from Chinese factories or specifying to IEC standards, you'll encounter metric sizes. The nearest equivalents are shown in the table above, but be aware:

AWG and metric sizes don't match exactly — a 2.5 mm² conductor is close to but not identical to 14 AWG (2.08 mm²)
For exact equivalence, always specify the actual cross-section in mm² rather than relying on "nearest equivalent"
Medium and large conductor sizes (above 10 AWG / 6 mm²) have closer IEC equivalents than small gauge wire

Typical Applications by AWG

AWG Range	Typical Applications
4/0 – 1/0 AWG	Service entrance, large feeders, 200–400A panels
1 – 4 AWG	Sub-panel feeders, large motor feeders, EV charging
6 AWG	50A circuits (EVSE, range, A/C), large appliances
8 AWG	40–50A circuits, dryers, water heaters
10 AWG	30A circuits, A/C units, small appliances
12 AWG	20A branch circuits, kitchen/bathroom outlets
14 AWG	15A branch circuits, general lighting
16–18 AWG	Fixture leads, appliance cords, lamp wire
20–22 AWG	Low-voltage control, thermostats, signal wire

Frequently Asked Questions

What AWG wire is used for standard house wiring?

Standard US residential wiring uses 14 AWG for 15A branch circuits and 12 AWG for 20A branch circuits. Large appliance circuits use 10 AWG for 30A circuits. Service entrance for a 200A panel is typically 4/0 AWG copper or 350 kcmil aluminum.

How do I convert AWG to mm²?

Use the table above for standard sizes. The formula is: cross-section (mm²) = 0.012668 × 92^((36−AWG)/19.5). Common conversions: 14 AWG = 2.08 mm², 12 AWG = 3.31 mm², 10 AWG = 5.26 mm², 8 AWG = 8.37 mm².

What is the largest AWG wire size?

4/0 AWG (0000 AWG) is the largest standard AWG size at ~107 mm². For conductors larger than 4/0 AWG, the American system switches to kcmil (thousands of circular mils), with common sizes of 250 kcmil, 350 kcmil, 500 kcmil, and 750 kcmil used for service entrance and large feeder applications.