Wire gauge conversions built from the published standards by an engineer who specifies cable for a living.
Why This Site Exists
Converting a wire gauge is easy arithmetic. Every calculator on the internet does it.
The problem is what happens next. 12 AWG converts to 3.31 mm², and no cable is manufactured in that cross-section. So you round to a standard size — but which one, and what does that change? Most conversion sites stop at the arithmetic and leave you there.
I built AWGtoMM2.com to go one step further. Every conversion here comes with the metric size you can actually order, the resistance limit that size has to meet, and the conductor diameter you need for glands and lugs.
Our mission is to answer the question behind the question. Not just what the gauge converts to, but what you put on the purchase order.
Meet the Author
Zakaria El Intissar Automation & Industrial Computing Engineer
I’m an automation and industrial computing engineer with over 12 years of hands-on experience in power system automation and electrical protection. Specifying and terminating cable is part of the job — substation wiring, PV plant installations, control panels, and instrumentation loops.
I started this site after watching the same confusion repeat itself. Someone converts a gauge, writes the result on a drawing, and it comes back at the review because the number does not exist as a product. Or worse, it passes review and fails a conductor resistance test at the factory.
The information needed to avoid that is in the standards. It is just not in any converter.
Areas of Expertise
- Power system automation and control
- Electrical protection systems
- Substation and PV plant installation
- Industrial computing and SCADA
- Cable specification and field termination
What You’ll Find Here
This site is organized into four sections:
Wire Sizes — One page per gauge, from 4/0 down to 44 AWG. The conductor diameter in mm, the cross-section in mm², the metric size that replaces it, and what that gauge is actually used for.
Metric Sizes — The other direction. Every standard metric size from 0.5 to 630 mm², with the closest gauge and the safe substitute.
Converters — The tools. AWG to mm and mm², metric back to AWG, kcmil, and the full reference chart.
Guides — How the gauge system works, why diameter and cross-section give different answers, what the stranding classes mean, and where the two measurement systems disagree.
Our Approach
Every page on this site follows a few simple rules:
Traceable numbers — Diameters and areas come from the ASTM B258 table. Metric sizes, resistance limits, stranding classes and conductor diameters come from IEC 60228. Nothing is estimated or copied from another website.
The rounding is stated, not hidden — When a conversion lands between two standard sizes, the site says so and shows how much copper is in the gap. That gap is sometimes 12% and sometimes 144%.
Plain language — Technical topics don’t need complicated writing. Short sentences, no filler, written the way a colleague would explain it on site.
What this site will not do — It will not tell you the ampacity of a conductor without knowing the installation method, the ambient temperature, and how many conductors share the raceway. It will not tell you that an AWG size “equals” a metric size, because on a specification it does not. Where the answer depends on the governing code, the site says so instead of guessing.
Get in Touch
Found a value that doesn’t match the standard you hold? Want a size or a calculator added?
I’d like to hear from you. Reach out through the contact page or email me directly at contact@awgtomm2.com.
You can also connect with me on LinkedIn.