0.0747 inch. or 1.89 mm
19 gauge steel is 1.11 mm thick and 20 gauge is .953 mm thick.
thick
11 gauge steel is 0.125 inches thick.
it is approx the thickness of a penny
16 gauge
17 gauge = 1.422 mm
18 gauge is thicker than 20 gauge. 18 gauge is 1.27 mm thick while 20 gauge is .953 mm thick.
Probably 25 gauge, which is .556 mm thick. However, 26 gauge is close too, it is .478 mm thick.
In Imperial standard (swg), 16 g is 0.064" (1.63mm) thick.
It is .478 mm thick.
4mm sheet metal falls 24 gauge and 25 gauge. 24 gauge sheet metal is 3.175mm (0.125") thick, and 25 gauge sheet metal is 6.35 (0.25") mm thick.