Wire Gauge Chart — AWG Sizes, Resistance & Ampacity

AWG wire gauge chart with mm², diameter, resistance per km and current-carrying capacity.

About this calculator

An American Wire Gauge (AWG) reference chart converts AWG numbers to wire diameter (in inches and millimetres), cross-sectional area, resistance per metre, and safe ampacity for current-carrying conductors. AWG is the standard wire gauge system used in the USA and most of the world for electrical wiring.

As with cannulas, AWG uses an inverse scale: smaller AWG numbers indicate thicker wire. 14 AWG (residential lighting) is thicker than 22 AWG (electronics signal wire). Each step down in AWG (e.g. 14 to 13) increases the cross-sectional area by ≈ 26% — meaning 3 AWG steps roughly double the area and halve the resistance.

Formula

d = 0.005 \times 92^{(36-n)/39} \text{ inches}

  • n — AWG number
  • d — Wire diameter in inches
  • Note — Each AWG step changes diameter by a factor of 92^(1/39) ≈ 1.0596

Worked example

Inputs: 12 AWG copper wire (typical for kitchen circuits in the USA)

  1. Diameter = 0.0808 inches = 2.05 mm
  2. Cross-sectional area = 3.31 mm² (6.53 mm² for 10 AWG, 1.31 mm² for 16 AWG)
  3. Resistance: 5.21 Ω/km at 20 °C
  4. Ampacity (60 °C cable in conduit, 75 °C insulation): 25 A continuous

Frequently asked questions

AWG or mm² for Indian wiring?

Indian electrical practice uses mm² (cross-section in square millimetres) per IS 694. Use 1.0 mm² for lighting, 1.5–2.5 mm² for general power outlets, 4–6 mm² for AC and high-load circuits, and 10–16 mm² for sub-mains. Conversion: 1 AWG ≈ 0.5 mm², 14 AWG ≈ 2.08 mm², 10 AWG ≈ 5.26 mm².

What ampacity can each wire size carry?

Approximate continuous current (copper conductor, 60 °C ambient, in conduit): 1.5 mm² = 13 A, 2.5 mm² = 18 A, 4 mm² = 24 A, 6 mm² = 31 A, 10 mm² = 43 A, 16 mm² = 60 A. These are conservative values per IS 3961; consult local codes for the actual ampacity table that applies to your installation method, insulation type, and ambient temperature.

Related calculators

Sheet Metal Gauge Bolt Sizes Pipe Sizes

More calculators

EMI Calculator Mortgage Calculator SIP Calculator Compound Interest GST / VAT Calculator Salary Calculator Unit Converter Currency Converter Scientific Calculator Concrete Calculator Paint Calculator Tile Calculator Calorie / TDEE Body Fat Macro Calculator O-Ring Sizes Bolt & Nut Sizes Pipe Sizes Needle Gauge Chart IV Cannula Sizes Suture Sizes Catheter French Sizes Drug Dosage See all 90+ calculators ›