Wire Gauge Chart

Complete AWG, SWG, and metric wire gauge reference with ampacity, resistance, and voltage drop calculations.

Copper
Aluminum
Other
°C
Volts
Amps
%
Typically 3% for branch circuits, 5% for feeders
Wire Gauge Conversion Results
Diameter
2.05 mm
0.081 inches
Cross-Section Area
3.31 mm²
6,530 circular mils
Resistance (20°C)
5.21 Ω/km
1.59 Ω/1000ft
Ampacity (Copper)
20 A
60°C insulation
Max Current (Chassis)
41 A
Single wire in air
Weight (Copper)
29.4 kg/km
~19.8 lb/1000ft
Wire Diameter
2.05 mm
Wire Size Comparison
18 AWG
12 AWG
6 AWG
Safe ampacity (< 30% of max)
Moderate load (30-70% of max)
High load (> 70% of max)

Wire Gauge Reference Chart

Complete AWG wire gauge specifications with metric equivalents

AWG Diameter (in) Diameter (mm) Area (mm²) Area (kcmil) Resistance (Ω/1000ft) Ampacity (60°C) Max Current (chassis)
Showing 44 wire gauges

Wire Gauge Applications

Residential Wiring
  • 14 AWG: 15A lighting circuits
  • 12 AWG: 20A outlet circuits
  • 10 AWG: 30A appliances (dryers)
  • 6-8 AWG: 40-50A ranges, EV chargers
Automotive Wiring
  • 18-20 AWG: Signal wires, sensors
  • 14-16 AWG: Lighting, accessories
  • 10-12 AWG: Fuel pumps, fans
  • 4-8 AWG: Starter, battery cables
Electronics
  • 22-30 AWG: PCB traces, jumpers
  • 18-24 AWG: Hook-up wire
  • 14-20 AWG: Power supply wiring
  • Solid vs Stranded: Use stranded for flexibility
Solar & Renewable Energy
  • 10-12 AWG: Solar panel strings
  • 2-8 AWG: Battery connections
  • 1/0-4/0 AWG: Inverter connections
  • Consider voltage drop for long runs

Safety Note: Always follow local electrical codes (NEC, IEC, etc.) when selecting wire sizes. The ampacity values shown are for general reference and may need adjustment based on installation conditions, ambient temperature, and insulation type.

Understanding Wire Gauges

1

AWG (American Wire Gauge): The standard wire sizing system in North America. AWG numbers decrease as wire diameter increases (e.g., 10 AWG is thicker than 14 AWG). Each 3-gauge decrease doubles the cross-sectional area.

2

SWG (Standard Wire Gauge): Also known as British Standard Wire Gauge, used primarily in the UK. SWG sizes differ from AWG, especially for smaller diameters.

3

Metric Wire Sizes: Measured in square millimeters (mm²) of cross-sectional area. Common metric sizes include 0.5mm², 1.5mm², 2.5mm², 4mm², 6mm², 10mm², 16mm², etc.

Key Electrical Properties

Ampacity

The maximum current a wire can carry continuously under specified conditions without exceeding its temperature rating. Affected by insulation type, ambient temperature, and installation method.

Voltage Drop

The reduction in voltage in an electrical circuit between the source and load. For long wire runs, voltage drop can be significant and may require larger wire sizes.

Resistance

Opposition to current flow, measured in ohms per unit length. Increases with temperature and decreases with larger wire cross-sectional area.

Skin Effect

At high frequencies, current tends to flow near the surface of a conductor, effectively reducing the usable cross-section. Important for AC circuits and RF applications.

Wire Selection Guidelines

Important Considerations:

  • Current Capacity: Select wire based on maximum expected current, not average load
  • Voltage Rating: Ensure wire insulation is rated for circuit voltage
  • Temperature Rating: Consider ambient temperature and wire insulation rating
  • Mechanical Strength: Thinner wires are more susceptible to breakage
  • Voltage Drop: For long runs, calculate voltage drop to ensure proper equipment operation

Frequently Asked Questions

AWG (American Wire Gauge) and SWG (Standard/British Wire Gauge) are different wire sizing standards. While they follow similar principles (smaller numbers = larger wires), they have different diameter specifications for the same gauge number. For example, 10 AWG has a diameter of 2.588 mm, while 10 SWG has a diameter of 3.251 mm. AWG is used primarily in North America, while SWG is more common in the UK.

The most accurate method is to use cross-sectional area. Common conversions include: 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. However, these are approximate; for precise conversions, use the calculator above which accounts for the exact specifications.

Wire resistance increases with temperature, which means more heat is generated at the same current. Higher ambient temperatures reduce the wire's ability to dissipate heat, so ampacity must be reduced to prevent overheating. Insulation type also matters - wires with higher temperature-rated insulation (e.g., 90°C vs 60°C) can carry more current at the same ambient temperature.

Voltage drop becomes significant when wire runs are long (typically over 50 feet/15 meters for branch circuits) or when high currents are involved. As a general rule, aim for less than 3% voltage drop for branch circuits and 5% for feeders. Excessive voltage drop can cause equipment to malfunction, reduce efficiency, and cause motors to overheat.

Solid wire consists of a single conductor, while stranded wire is made of multiple smaller wires twisted together. Solid wire is cheaper, easier to terminate, and has slightly better current capacity for the same gauge. Stranded wire is more flexible, resistant to metal fatigue from vibration, and easier to route in tight spaces. For applications with movement or vibration, stranded wire is generally preferred.