MM to Wire Gauge Calculator – Convert Any Diameter Instantly

⚡ MM to Wire Gauge Calculator

Convert wire diameter (mm) to AWG or SWG gauge — get cross-section area, ampacity & resistance

⚡ Quick Presets

📏 Wire Specifications

Unit System

Gauge Standard

Wire Diameter (mm)

Wire Length

Conductor Material

Wire Application

Wire Type

Temperature Rating (°C)

📊 Wire Gauge Conversion Results

🧲 Wire Material Properties

1.72

Copper Resistivity (μΩ⋅cm)

2.82

Aluminum Resistivity (μΩ⋅cm)

8.9

Copper Density (g/cm³)

2.7

Aluminum Density (g/cm³)

2.24

Silver Resistivity (μΩ⋅cm)

10.0

Steel Resistivity (μΩ⋅cm)

60%

Al Conductivity vs Cu

99.9%

Cu IACS Conductivity

📋 AWG Complete Reference Table

AWG	Diameter (mm)	Diameter (in)	Area (mm²)	Resistance (Ω/km Cu)	Ampacity 60°C	Ampacity 75°C	Ampacity 90°C
4/0 (0000)	11.684	0.4600	107.2	0.1608	195A	230A	260A
3/0 (000)	10.405	0.4096	85.01	0.2028	165A	200A	225A
2/0 (00)	9.266	0.3648	67.43	0.2557	145A	175A	195A
1/0 (0)	8.251	0.3249	53.48	0.3224	125A	150A	170A
1	7.348	0.2893	42.41	0.4066	110A	130A	150A
2	6.544	0.2576	33.63	0.5127	95A	115A	130A
4	5.189	0.2043	21.15	0.8152	70A	85A	95A
6	4.115	0.1620	13.30	1.296	55A	65A	75A
8	3.264	0.1285	8.367	2.060	40A	50A	55A
10	2.588	0.1019	5.261	3.277	30A	35A	40A
12	2.053	0.0808	3.309	5.211	20A	25A	30A
14	1.628	0.0641	2.081	8.286	15A	20A	25A
16	1.291	0.0508	1.309	13.17	13A	13A	18A
18	1.024	0.0403	0.8231	20.95	10A	14A	16A
20	0.8118	0.0320	0.5176	33.31	—	11A	13A
22	0.6438	0.0253	0.3255	52.97	—	7A	—
24	0.5106	0.0201	0.2047	84.22	—	3.5A	—
26	0.4049	0.0159	0.1288	133.9	—	2.2A	—
28	0.3211	0.0126	0.0810	212.9	—	0.83A	—
30	0.2546	0.0100	0.0509	338.6	—	0.52A	—

📋 SWG (Standard Wire Gauge) Reference

SWG	Diameter (mm)	Diameter (in)	Area (mm²)	Resistance (Ω/km Cu)	Common Use
0000 (4/0)	10.160	0.4000	81.07	0.212	Heavy power cables
000 (3/0)	9.144	0.3600	65.61	0.263	Power distribution
00 (2/0)	8.230	0.3240	53.16	0.324	Main feed cables
0 (1/0)	7.620	0.3000	45.60	0.378	Service entrance
2	7.010	0.2760	38.59	0.446	Heavy equipment
4	5.893	0.2320	27.27	0.631	Sub-panels
6	4.877	0.1920	18.69	0.921	Appliance wiring
8	4.064	0.1600	12.97	1.326	Range / dryer
10	3.251	0.1280	8.302	2.074	A/C units
12	2.642	0.1040	5.480	3.143	General circuits
14	2.032	0.0800	3.243	5.312	Lighting circuits
16	1.626	0.0640	2.076	8.302	Low power loads
18	1.219	0.0480	1.167	14.77	Instrumentation
20	0.9144	0.0360	0.6567	26.23	Control wiring
24	0.5588	0.0220	0.2452	70.30	Signal wiring
28	0.3759	0.0148	0.1110	155.3	Transformer wire
32	0.2743	0.0108	0.0591	291.6	Fine winding wire
36	0.1930	0.0076	0.0293	588.3	Coil winding

🔧 Common Applications Reference

Application	AWG Range	Typical Diameter	Material	Notes
Residential 15A Circuit	14 AWG	1.628 mm	Copper	NEC requires 14 AWG min for 15A
Residential 20A Circuit	12 AWG	2.053 mm	Copper	Kitchens, bathrooms
30A Dryer Circuit	10 AWG	2.588 mm	Copper	240V dedicated circuit
50A Range Circuit	6 AWG	4.115 mm	Copper/Al	Electric range / oven
Automotive Chassis	18–22 AWG	0.64–1.02 mm	Copper	Stranded for flex
Automotive Starter	2–4 AWG	5.19–6.54 mm	Copper	High current, short run
PCB Signal Wire	24–28 AWG	0.32–0.51 mm	Copper	Low current signals
USB Cable	28 AWG	0.321 mm	Copper	Stranded, tinned
Speaker Wire (HiFi)	12–16 AWG	1.29–2.05 mm	Copper	OFC preferred
Guitar Pickup Wire	42–44 AWG	0.063–0.079 mm	Copper	Enameled magnet wire
Solar Panel Feed	10–12 AWG	2.05–2.59 mm	Copper	UV-rated insulation
Control Panel (PLC)	14–16 AWG	1.29–1.63 mm	Copper	Stranded, 75°C rated

💡 AWG Formula: AWG gauge n has diameter d = 0.127mm × 92^(36-n)/39. Larger AWG number = smaller wire. Every 6 gauge steps halves the wire area; every 3 steps changes diameter by ~41%. For stranded wire, the overall diameter is approximately 15–20% larger than the equivalent solid conductor.

💡 Resistance Calculation: Wire resistance R = ρ × L / A, where ρ is resistivity (Ω⋅m), L is length (m), and A is cross-section area (m²). Copper ρ = 1.72 × 10^-8 Ω⋅m at 20°C. Resistance increases by ~0.393% per °C for copper. Always use the next larger wire size when operating near the rated ampacity.

Always wear appropriate safety equipment when working with electrical wiring. Never exceed the rated ampacity of wire at its temperature rating. Verify all gauge selections comply with NEC or applicable local electrical code before installation.

The rating of wires simply serves as method for showing the real size of wire. It helps to know how much electricity the wire can handle without danger of overheating. The size relates directly to the diameter of the wire itself.

Here commonly happens confusion between folks: rather than expected lower rating shows thicker wire. For instance, wire of 10 rating is much fatter than that of 14 rating. The relation flips; if you climb in the ratings, the wire becomes entirely thinner.

How to Choose the Right Wire Size

In United States, the standard use is AWG (American System of wire Ratings). This standard exists since almost 1857, so it is well set. One applies it mainly in North America for measuring round or solid, metal cables, that carry electricity.

The full details appear in the standard ASTM B 258. Instead of simply saying “this many inches” or “this many millimeters”, the AWG assigns to every wire size its unique rating. Usually, when some mention AWG, one means copper wires.

The mode to produce wires really stikcs, if one thinks it. One draws metallic rod through special plate for pulling, and every passage thins the wire a bit more. In short, it is repeatable cold pressure.

Also exist practical tools, designed specially for checking wire ratings. Those are commonly round or oval discs with slices around the banks in different sizes. Every slice bears stamped rating, and you simply slide the wire to sea, what answers.

Some prefer to use calipers instead and measure the diameter themselves. Wire of 8 AWG measures around 0.1285 inches, while 10 AWG arrives at approximately 0.1019 inches. On the other hand, AWG is not the only method.

The British SWG was once very spread, and there is also a metric version with square millimeters for the cross area.

What rating you choose, depends mainly on what you plan to do with the wire. For wire that bears little power over short ways, ratings of 16 to 18 AWG suffice for the task. 14 AWG acts as reliable all-purpose option for many cases.

At long cable runs, low resistance or high power, one requires 12 AWG or even thicker. While breadboarding of circuits, 18 rating answers for medium power cable, 22 rating bears light loads up to around 1 ampere, and 30 rating serves for signal-only ties.

The voltage drop forms another important reason for care about rating choice. If you pass 1.6 amperes through 12-rating wire in 40 feet, the drop stays only around 0.2 volts. At less thick ratings, the toll grows clearly.

14 rating shows about 0.3 volts, 16 rating around 0.5 volts, and 20 rating reaches 1.2 volts. Choose the right rating to ensure safe flow withoutlost impact. The diameter of wires almost doubles itself every six ratings, what helps fast rating in mind.

Author

Thomas Martinez

Hi, I am Thomas Martinez, the owner of ToolCroze.com! As a passionate DIY enthusiast and a firm believer in the power of quality tools, I created this platform to share my knowledge and experiences with fellow craftsmen and handywomen alike.

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