Reference

The tables, unconverted

Wire and sheet goods are sold to different standards in different countries. These tables set the two systems side by side and name the gap between them, rather than pretending one translates cleanly into the other.

AWG sizes14

Metric sizes15

Undersizing traps4

Sheet standards4

AWG to mm²

The middle column is the metric size closest to the American conductor, not an equivalent. Where it holds less copper the row is amber, because that is the substitution that quietly undersizes a circuit.

AWG	True area	Closest stocked	Difference	Ampacity, 12V bundled
18	0.823 mm²	0.75 mm²	−0.07 mm² less copper	7 A
16	1.31 mm²	1.5 mm²	+0.19 mm²	10 A
14	2.08 mm²	2.5 mm²	+0.42 mm²	15 A
12	3.31 mm²	4 mm²	+0.69 mm²	25 A
10	5.26 mm²	6 mm²	+0.74 mm²	35 A
8	8.37 mm²	10 mm²	+1.63 mm²	50 A
6	13.3 mm²	16 mm²	+2.70 mm²	65 A
4	21.2 mm²	25 mm²	+3.80 mm²	85 A
2	33.6 mm²	35 mm²	+1.40 mm²	110 A
1	42.4 mm²	35 mm²	−7.40 mm² less copper	not published
1/0	53.5 mm²	50 mm²	−3.50 mm² less copper	135 A
2/0	67.4 mm²	70 mm²	+2.60 mm²	not published
3/0	85 mm²	95 mm²	+10.00 mm²	not published
4/0	107.2 mm²	95 mm²	−12.20 mm² less copper	not published

Size a run with the calculator →

Plywood sheet sizes

Metric	Imperial	Markets	Note
1220 × 2440 mm	4 ft × 8 ft	US, CA, UK	The most widely stocked sheet. Nominally 4×8 ft, milled to 1220 × 2440 mm.
1250 × 2500 mm	metric only	EU	Continental European metric format. 60 mm longer and 30 mm wider than the UK sheet, and not interchangeable with it.
1200 × 2400 mm	metric only	AU, NZ	Common Australian and New Zealand format. Note that 1220 × 2440 mm is also stocked in some AU suppliers, so confirm before cutting.
1525 × 1525 mm	5 ft × 5 ft	US, CA, UK, EU, AU	Baltic birch is square. A nesting diagram drawn for a 4×8 sheet does not apply to it at all.

Battery chemistry

Usable depth of discharge, Peukert exponents, cycle life and cold-weather capacity for LiFePO4, AGM, gel and flooded lead acid live alongside the tool that uses them, rather than being repeated here where the two copies would only compete with each other.

Battery chemistry reference →

Nominal against actual thickness

A US sheet sold as three quarters of an inch measures 18.26 mm, because the plies lose moisture in the kiln, the stack is compressed under heat, and the faces are sanded. A metric 18 mm sheet measures 18 mm. The gap is small and it is the difference between a dado that holds and one that rattles.

Sold as	Actually	System	Never substitute for
3/4 in	18.26 mm	imperial	18 mm
18 mm	18 mm	metric	3/4 in
1/2 in	11.91 mm	imperial	12 mm
12 mm	12 mm	metric	1/2 in
3/8 in	9.13 mm	imperial	9 mm
9 mm	9 mm	metric	3/8 in
15 mm	15 mm	metric	—