AWG to mm² Conversion Chart
Complete reference for converting between American Wire Gauge (AWG) and metric cross-section (mm²), with ampacity and resistance for copper conductors. Used for RV, marine, and off-grid DC wiring.
All values assume copper at 20°C ambient. Looking for the reverse direction? See mm² to AWG.
AWG to mm² Reference Table
Standard pairings used in international cable sizing. Click any row with a detail page to see voltage drop tables, fuse sizing, and applications for that gauge.
| AWG | mm² | Ampacity | Resistance (mΩ/m) | Typical Use | Details |
|---|---|---|---|---|---|
| 18 AWG | 0.75 mm² | 7 A | 23.20 | Signal wires, low-power LEDs | View → |
| 16 AWG | 1 mm² | 10 A | 17.80 | Interior lights, small fans | — |
| 14 AWG | 1.5 mm² | 15 A | 11.90 | Standard lighting circuits | View → |
| 13 AWG | 2.5 mm² | 20 A | 7.14 | 12V branch circuits, USB outlets | — |
| 12 AWG | 4 mm² | 25 A | 4.46 | Water pumps, USB chargers | View → |
| 10 AWG | 6 mm² | 35 A | 2.98 | Fridges, MPPT to battery | View → |
| 8 AWG | 10 mm² | 50 A | 1.78 | Sub-panels, DC-DC chargers | — |
| 6 AWG | 16 mm² | 65 A | 1.12 | Inverter feeds, shore-power chargers | — |
| 4 AWG | 25 mm² | 85 A | 0.71 | Battery interconnects, mid inverters | View → |
| 2 AWG | 35 mm² | 110 A | 0.51 | Heavy battery cables | — |
| 1 AWG | 50 mm² | 135 A | 0.36 | Large inverters, main battery leads | — |
| 1/0 | 70 mm² | 170 A | 0.26 | 1/0 — high-power inverters | — |
| 2/0 | 95 mm² | 200 A | 0.19 | 1/0 AWG (50 mm²) | — |
| 3/0 | 120 mm² | 235 A | 0.15 | 2/0 — high-power bus bars | — |
| 4/0 | 150 mm² | 285 A | 0.12 | 3/0 — bow thrusters, windlasses | — |
| 5/0 | 185 mm² | 330 A | 0.10 | 4/0 — high-power marine | — |
| 6/0 | 240 mm² | 400 A | 0.07 | 300 MCM — industrial DC | — |
Ampacity values are for copper conductors in chassis wiring at 20°C ambient. Free-air ratings are higher; engine-bay or bundled-cable installations are lower (derate 10–20%).
Detailed Conversion Pages
Each page below has voltage drop tables for 12V and 24V, fuse sizing, applications, and FAQs specific to that gauge.
18 AWG (0.75 mm²) is the thinnest standard cable still considered "wiring" in DC systems — below it, you are into signal-wire and pre-tinned BMS-cable territory. It handles small loads under 7 A: indicator LEDs, low-power dome lights, sensor feeds, and the trigger sides of relays. In stocked metric markets, 0.75 mm² is the smallest cable typically sold off the spool, available alongside 1.0 mm² and 1.5 mm². Anything below 0.75 mm² is usually multi-conductor sheathed cable for trailer plugs or sensor harnesses.
12 AWG (4 mm²) is the workhorse of 15–25 A DC circuits. It is the gauge most camper builders pick for the water pump, vent fan, and USB charger branches — heavier than the 14 AWG lighting circuit, lighter than the 10 AWG fridge feed. In 12V automotive applications it is the standard for accessory sockets, electric awnings, dual-purpose Maxxair fans, and small inverter feeds up to roughly 300 W. The metric pair is 4 mm², stocked in every auto-electrical shop in Europe.
10 AWG is the workhorse of medium-current DC wiring. It handles the loads that are too heavy for general lighting (14 AWG / 12 AWG) but lighter than direct battery interconnects (8 AWG and above). In a typical camper or boat, 10 AWG runs from the fuse panel to the compressor fridge, the heater fan, and from the MPPT solar charge controller to the battery on systems up to roughly 30 amps.
14 AWG is the gauge most camper electricians default to for branch circuits in the 5–15 A range. It handles interior LED lighting, USB outlets, small fans, and 12V cigarette sockets without breaking a sweat. Below 14 AWG you are into signal-wire territory (16 / 18 AWG); above it (12 AWG) is for water pumps, vent fans, and small motor loads. In standard metric cable, 14 AWG corresponds to 1.5 mm² — the most stocked size in European auto-electrical and marine shops.
4 AWG is where DC wiring stops being light branch circuits and starts being serious power transmission. It is the default for battery bank interconnects, feeds to medium inverters (1000–1500 W class at 12V), and the main distribution between battery and fuse panel. At this gauge, friction-fit terminals stop being acceptable — every 4 AWG termination needs a hexagonal crimp die, heat-shrink, and ideally a torque-checked stud connection.
AWG to mm² Calculator
For any custom load and cable length, use the wire gauge calculator. It returns the recommended AWG and mm² size, voltage drop, power loss, and fuse rating.
= 60W
= 16.4 ft (one way, round-trip calculated automatically)
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Result
Fuse Size
Materials
- Battery cable2.5 mm² · 2 × 6 m
- Fuse7.5 A · Blade (ATC/ATO) · × 1
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Download Cable for iOSFrequently Asked Questions
How do I convert AWG to mm²?
AWG (American Wire Gauge) maps to specific cross-section areas in mm². The exact formula uses circular mils, but the standard pairings used in international cable sizing are: 18 AWG = 0.75 mm², 16 AWG = 1.0 mm², 14 AWG = 1.5 mm², 12 AWG = 4.0 mm², 10 AWG = 6.0 mm², 8 AWG = 10 mm², 6 AWG = 16 mm², 4 AWG = 25 mm². Use the chart above for the full table or the calculator for any custom conversion.
Why does AWG number get smaller as wire gets thicker?
AWG is a logarithmic scale based on the historical drawing process — the gauge number was the count of times a wire was drawn through a die to reach a given diameter. Each step down (e.g., 12 AWG to 10 AWG) increases cross-section by ~26%. Below 1 AWG the scale switches to fractional notation: 1/0 (one-aught), 2/0, 3/0, 4/0.
What is the difference between metric mm² and AWG?
mm² describes the actual cross-section area of the conductor in square millimeters — a direct measurement. AWG is the historical American gauge number. mm² values are continuous; AWG values are discrete steps. International cable standards pair specific AWG sizes with specific mm² sizes, and they are interchangeable in datasheets.
Does the conversion change for aluminum wire?
No — the AWG to mm² conversion is purely geometric (cross-section area), so it is the same for any conductor material. However, the ampacity values change: aluminum has ~60% higher resistance than copper for the same cross-section, so an aluminum wire of the same AWG carries less current. All values on this page assume copper.
What is the most common AWG size for 12V camper wiring?
14 AWG (1.5 mm²) for general lighting and accessories, 12 AWG (4 mm²) for water pumps and USB outlets, 10 AWG (6 mm²) for compressor fridges and MPPT-to-battery feeds, and 4 AWG (25 mm²) for inverter feeds up to ~1000W. Battery interconnects on lithium banks typically use 2 AWG (35 mm²) or 1/0 AWG (50 mm²).
Wiring Diagram Maker
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Wire Gauge Calculator
Custom voltage, current, and length inputs with voltage drop, power loss, and fuse recommendations.
Reverse: mm² to AWG
Same chart, indexed by metric cross-section — 0.75 mm² through 240 mm².