Skip to main content
Book Consultation →
Electronics100% FreeInstant

AWG Wire Gauge Calculator: Diameter, Area and Resistance

This free AWG calculator converts an American Wire Gauge number into the wire diameter in millimetres and inches, the cross-section area and the resistance of copper wire. It can also find the gauge from a diameter.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

AWG sizes wire in a way that can seem backwards. A bigger number means thinner wire. Electronics, audio, cabling and electrical work all use it.

Enter the AWG number or the diameter and see the rest.

How to Use This Tool

  1. Choose whether you know the AWG or the diameter.
  2. Enter the value.
  3. Optionally enter a length for total resistance.
  4. Press Calculate.

How the Calculation Works

The diameter follows d = 0.127 × 92^((36 − n) ÷ 39) mm. Area = π × d² ÷ 4. Resistance per kilometre = 1.724e-8 × 1000 ÷ area in square metres. Going from a diameter to a gauge, n = 36 − 39 × log(d ÷ 0.127) ÷ log(92).

Worked Example

AWG 18 has a diameter of 1.024 mm and an area of 0.823 mm², and copper resistance of about 20.9 ohms per km. AWG 10 is 2.588 mm and 5.26 mm².

Common Uses

  • Choosing wire for projects.
  • Audio and speaker cable.
  • Estimating voltage drop.
  • Converting to metric sizes.

Tips and Common Mistakes

  • Thicker wire carries more current with less loss.
  • Stranded wire has slightly higher resistance than solid.
  • Use the current ratings in your local code.

Next, you may need the Ohm’s law calculator, LED resistor calculator, resistor color code calculator, electricity cost calculator.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

American Wire Gauge, a standard set of wire sizes. A smaller number means a thicker wire, and every 6 gauges the diameter halves.
Diameter in mm = 0.127 × 92^((36 − AWG) ÷ 39).
Resistance = resistivity × length ÷ area, using 1.724 × 10⁻⁸ ohm-metres for copper at 20 °C.
No. How much current a wire can carry depends on insulation, temperature and the code that applies. Check the correct tables.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.