How do you convert AWG to mm²?

AWG 10 = 5.26 mm², AWG 12 = 3.31 mm², AWG 14 = 2.08 mm². The formula is: mm² = 0.012668 × 92^((36-AWG)/19.5). Or use the reference table in this calculator for common conversions.

What AWG wire should I use for solar panels?

Panel-to-combiner: 10-12 AWG PV wire. Combiner to inverter/charge controller: 4-8 AWG based on current. Battery cables: 2/0-4/0 AWG for high-current DC. Always size at 125% of actual current per NEC.

AWG to mm² Calculator

Convert American Wire Gauge (AWG) to metric mm² and back. Includes full table with diameter, resistance, and ampacity for every gauge.

Wire gauge input

AWG gauge?

Wire specifications

10 AWG = 5.26 mm²

Diameter2.59 mm

Resistance3.280 mΩ/m

Ampacity (free air)55 A

Ampacity (conduit)35 A

AWG Reference Table

AWG	mm²	Diam (mm)	Res (mΩ/m)	Amp (free)	Amp (conduit)
4/0 (0000)	107.2	11.68	0.161	360	230
3/0 (000)	85	10.4	0.203	302	200
2/0 (00)	67.4	9.27	0.256	265	175
1/0 (0)	53.5	8.25	0.323	230	150
1	42.4	7.35	0.407	195	130
2	33.6	6.54	0.513	170	115
3	26.7	5.83	0.647	145	100
4	21.1	5.19	0.815	125	85
6	13.3	4.11	1.300	101	65
8	8.37	3.26	2.060	73	50
10	5.26	2.59	3.280	55	35
12	3.31	2.05	5.210	41	25
14	2.08	1.63	8.280	32	20
16	1.31	1.29	13.160	22	13
18	0.823	1.02	20.930	16	10
20	0.518	0.812	33.280	11	7
22	0.326	0.644	52.940	7	5
24	0.205	0.511	84.200	3.5	3
26	0.129	0.405	133.900	2.2	2
28	0.081	0.321	212.900	0.83	0.7
30	0.0509	0.255	338.600	0.52	0.5

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How to Use This Calculator

Choose conversion direction

Select AWG → mm² to look up a US wire gauge, or mm² → AWG to find the closest AWG equivalent for a metric wire size. The AWG direction shows exact specifications; the mm² direction finds the nearest standard AWG gauge.

Select or enter your gauge

For AWG mode, select the gauge from the dropdown (4/0 to 30). For mm² mode, enter the cross-sectional area in square millimeters — common IEC values are 1.5, 2.5, 4, 6, 10, 16 mm². The calculator finds the closest AWG equivalent.

Read the specifications

Results show the wire's cross-sectional area, diameter, resistance per meter, and ampacity — both in free air and in conduit. Use the full reference table below the calculator to compare multiple gauges side-by-side.

AWG vs mm² Explained

American Wire Gauge (AWG) is the US standard for wire sizing. The AWG number is inversely proportional to wire size — lower AWG number means thicker wire. The scale runs from 4/0 (0000) as the thickest common residential wire down to 30 AWG for fine signal wire.

The IEC (International Electrotechnical Commission) standard used in Europe, Australia, and most of the world specifies wire by cross-sectional area in mm². Higher mm² numbers mean thicker wire — the opposite of AWG convention.

AWG to mm² (approximate): mm² = 0.012668 × 92^((36-AWG)/19.5) Diameter from AWG: d (mm) = 0.127 × 92^((36-AWG)/39) Resistance: R = resistivity (ρ) ÷ cross-section area (copper: ρ = 1.72 × 10&sup8; Ω·m at 20°C)

Example

Sizing wire for a 3,000W solar inverter at 48V DC

A 3,000W inverter at 48V draws 62.5A (3,000 ÷ 48). You need wire that handles at least 62.5A with a safety margin. NEC recommends sizing at 125% for continuous loads: 62.5 × 1.25 = 78.1A minimum.

Required current78.1 A minimum

Looking up AWG table4 AWG = 85A (free air)

AWG 4 cross-section21.1 mm²

EU equivalent25 mm² (next standard size)

4 AWG (21.1 mm²) is the minimum for free-air installations. If the wire runs through conduit with other wires, you'd need to derate — in that case, use 2 AWG (33.6 mm²) or the EU 35 mm² equivalent.

FAQ

Why does lower AWG mean thicker wire? ▼

AWG was originally a measure of how many times a wire was drawn through a die during manufacturing. More draws = thinner wire = higher gauge number. So 10 AWG wire has been drawn more times than 4 AWG, making it thinner. The system is counterintuitive but deeply entrenched in US electrical practice. Remember: in AWG, smaller number = bigger wire.

What AWG wire is used for residential solar in the US? ▼

For residential solar: panel-to-combiner box typically uses 10 or 12 AWG PV wire. Combiner to charge controller or inverter uses 4-8 AWG depending on current. Battery bank cables use 2/0 to 4/0 AWG for high-current DC runs. AC output from inverter to main panel uses 6-10 AWG. Always calculate the actual current (watts ÷ volts), apply the 125% NEC safety factor, and check the table for the minimum adequate gauge.

What is the difference between ampacity in free air vs conduit? ▼

Free air ampacity assumes the wire is exposed with air circulating around it for cooling. Conduit (enclosed) ampacity is lower because heat builds up in the conduit, especially when multiple wires run together. The NEC requires derating for conduit installations: typically 70-80% of free-air ratings when 4+ current-carrying conductors share a conduit. For solar installations, always use the conduit column if the wire runs through any enclosed raceway.

Can I use metric mm² wire in a US installation? ▼

Yes, with care. NEC 2020 now explicitly permits metric wire sizes. The key is to use the closest-sized or larger metric equivalent. For example, if you need 10 AWG (5.26 mm²), the nearest standard metric size is 6 mm² (slightly larger, slightly safer). Never use a smaller metric size as a substitute for a specified AWG gauge. Check your local authority having jurisdiction (AHJ) for any local requirements.