An AWG to mm converter translates American Wire Gauge numbers to their metric equivalents — wire diameter in millimeters and cross-sectional area in mm². In the AWG system, larger numbers mean thinner wires: AWG 4/0 is a thick 11.68 mm cable used for service entrances, while AWG 24 is a hair-thin 0.51 mm wire used in electronics. This tool also calculates voltage drop and shows current capacity (ampacity) for copper conductors.
AWG to mm Converter
Enter -3 for 4/0, -2 for 3/0, -1 for 2/0, 0 for 1/0
NM-B/Romex = 60°C · THWN = 75°C · THHN = 90°C
Results
mm to AWG Lookup
Closest Match
Voltage Drop Calculator
Voltage Drop Results
AWG Wire Gauge Reference Chart
Copper conductors · NEC Table 310.15(B)(16) ampacity · Resistance per 1000 ft at 20°C
| AWG | Dia (mm) | Area (mm²) | kcmil | Amps 60°C | Amps 75°C | Amps 90°C | Ω/1000ft |
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Click any row to load that AWG into the converter. Ampacity values are for single copper conductors in free air per NEC 310.15(B)(16). Always verify with local codes and a licensed electrician.
How to Use the AWG to mm Converter
The AWG to mm converter is an essential reference for anyone working with North American wire gauges alongside metric wiring standards. Whether you are replacing a European appliance, sizing a solar installation, or comparing datasheets, knowing how to convert AWG to millimeters saves time and prevents costly wiring mistakes.
Understanding the AWG System
AWG (American Wire Gauge) uses a counterintuitive numbering system: the lower the AWG number, the thicker the wire. The largest common gauge is 4/0 (0000) at 11.68 mm diameter, used for service entrance conductors. The smallest commonly used household wire is AWG 14 at 1.63 mm. The scale is logarithmic — every 6 AWG steps roughly halves the cross-sectional area, and every 3 steps halves the diameter.
Step 1: Use the AWG Lookup Tab
Type an AWG number or select a preset from the dropdown. Enter -3 for 4/0 (0000), -2 for 3/0 (000), -1 for 2/0 (00), and 0 for 1/0. The tool returns the wire diameter in mm, cross-sectional area in mm² and kcmil, and the ampacity (current-carrying capacity) for the selected temperature rating — 60°C for NM-B/Romex, 75°C for THWN, or 90°C for THHN insulation.
Step 2: Reverse Lookup (mm to AWG)
If you know a metric wire size and need to find the AWG equivalent, use the Reverse Lookup tab. Enter either a cross-sectional area in mm² or a diameter in mm. The tool finds the closest standard AWG size and shows how close the match is. This is particularly useful when working with imported European cables labeled in mm² or when reading IEC-standard cable datasheets.
Step 3: Calculate Voltage Drop
The Voltage Drop tab lets you check whether a wire run meets the NEC recommended maximum of 3% voltage drop for branch circuits (5% total including feeders). Enter the AWG gauge, supply voltage, current draw in amps, and the one-way run length in feet or meters. The formula used is VD = 2 × L × R × I / 1000, where R is resistance in Ω/1000ft, L is the run length in feet, and I is current in amps. The factor of 2 accounts for the full circuit (hot + neutral). A color-coded bar shows whether your run is within the NEC limit.
Step 4: Browse the Full Reference Chart
The Full Chart tab displays the complete AWG reference table from 4/0 through AWG 40, including diameter, area in mm² and kcmil, ampacity at all three temperature ratings, and DC resistance per 1000 feet. Click any row to load that gauge into the AWG Lookup tab for more detail. The chart is based on NEC Table 310.15(B)(16) for copper conductors.
Common Wire Gauge Applications
Understanding which AWG is appropriate for each application is critical for safe electrical work:
- AWG 4/0–2/0: Service entrance conductors, large feeders, EV chargers (Level 2)
- AWG 6–4: Subpanels, electric ranges, EV charging stations, large motors
- AWG 10: 30-amp circuits, dryer outlets, HVAC units
- AWG 12: 20-amp household circuits, kitchen outlets, bathroom circuits
- AWG 14: 15-amp general purpose circuits, lighting, standard outlets
- AWG 16–18: Extension cords, lamp cord, low-voltage wiring
- AWG 20–24: Electronics, signal wire, thermostat wire, PCB traces
FAQ
Is this AWG to mm converter free?
Yes, the AWG to mm converter is completely free with no limits, no ads-walls, and no signup required. All conversions and calculations run instantly in your browser.
Is my data private when using this tool?
Yes, everything runs locally in your browser. No data is sent to any server, stored, or tracked. You can even use the tool offline after the page loads.
What is AWG and how does it relate to mm?
AWG (American Wire Gauge) is a standardized wire gauge system used in the US. Counterintuitively, a higher AWG number means a thinner wire. AWG 4/0 (0000) is 11.684 mm in diameter, while AWG 24 is only 0.511 mm. To convert, each 6 AWG increase halves the cross-sectional area.
What AWG wire should I use for a 20-amp circuit?
For a standard 20-amp 120/240V household circuit, use AWG 12 copper wire (rated 20A at 60°C). For longer runs where voltage drop matters, consider AWG 10. Always consult the NEC (National Electrical Code) and a licensed electrician for actual wiring projects.
How do I convert mm² to AWG?
Use the Reverse Lookup tab in this tool — enter a mm² value and it will find the closest AWG size. As a quick reference: 2.5 mm² ≈ AWG 13, 4 mm² ≈ AWG 11, 6 mm² ≈ AWG 10, 10 mm² ≈ AWG 8, 16 mm² ≈ AWG 6, 25 mm² ≈ AWG 4.
What is voltage drop and why does it matter?
Voltage drop is the reduction in voltage along a wire due to its resistance. For most residential circuits, the NEC recommends keeping voltage drop below 3% for branch circuits and 5% total. Excessive voltage drop causes equipment to underperform, motors to overheat, and lights to dim.
What is the difference between 60°C and 75°C ampacity ratings?
Ampacity depends on the wire's insulation temperature rating. 60°C-rated wire (like NM-B/Romex) has a lower safe current limit. 75°C-rated wire (like THWN) can carry more current. Most residential wiring uses 60°C ratings for terminations even if the wire is rated higher, per NEC 110.14(C).
Does AWG apply to both copper and aluminum wire?
AWG covers both copper and aluminum wire, but their ampacities differ. Aluminum has lower conductivity, so aluminum wire of the same AWG carries less current than copper — typically one to two sizes larger aluminum wire is needed to match copper's ampacity. This tool shows copper ampacity values.