Working from a metric drawing and need the American equivalent.
Converting metric to AWG has a complication the other direction does not. Metric sizes are real products, but the AWG conductor you get back is usually smaller — and a smaller conductor is not a substitution you can make quietly.
2.5 mm² is closest to 14 AWG by area. But 14 AWG has 17% less copper, so if you install it against a 2.5 mm² design you have downgraded the circuit. 12 AWG is the substitute that keeps you at or above the original.
That is why every page below gives two answers: the nearest gauge by area, and the safe substitute. They are rarely the same.
Every metric size
| Size | Solid diameter | Nearest AWG | Safe substitute |
|---|---|---|---|
| 0.5 mm² | 0.798 mm | 20 AWG | 20 AWG |
| 0.75 mm² | 0.977 mm | 18 AWG | 18 AWG |
| 1 mm² | 1.128 mm | 18 AWG | 16 AWG |
| 1.5 mm² | 1.382 mm | 16 AWG | 14 AWG |
| 2.5 mm² | 1.784 mm | 14 AWG | 12 AWG |
| 4 mm² | 2.257 mm | 12 AWG | 10 AWG |
| 6 mm² | 2.764 mm | 10 AWG | 8 AWG |
| 10 mm² | 3.568 mm | 8 AWG | 6 AWG |
| 16 mm² | 4.514 mm | 6 AWG | 4 AWG |
| 25 mm² | 5.642 mm | 3 AWG | 3 AWG |
| 35 mm² | 6.676 mm | 2 AWG | 1 AWG |
| 50 mm² | 7.979 mm | 1/0 AWG | 1/0 AWG |
| 70 mm² | 9.441 mm | 2/0 AWG | 3/0 AWG |
The diameter shown is the geometric equivalent for a solid conductor, d = 2√(S/π). It is not a specified value — the standard gives maximum diameters by construction class, not nominal ones.
Three sizes where the answer is clean
Most rows above need the safe substitute. Three do not.
0.5 mm² and 0.75 mm² map to 20 and 18 AWG closely enough that the nearest gauge is also the safe one.
25 mm² maps to 3 AWG in both columns. And 50 mm² maps to 1/0 both ways.
Those are the sizes where a metric drawing translates to American cable without a judgment call. Everywhere else, read both columns before you order.