As part of my electronics education I've been reading Teach Yourself Electricity and Electronics by Stan Gibilisco and Simon Monk. It's an American book so it uses American Wire Gauge (AWG), and I often need to convert to Standard Wire Gauge (SWG) — the British standard — or to metric. I made this calculator so I could do that more easily.

Examples of where I use it:

• What is this wire in the other system?

• For this length, what diameter wire do I need while keeping resistance under x ohms?