Steel Metal Door Thickness Explained

Gauge is a measurement of steel thickness. The principle is simple: the lower the gauge, the thicker the steel metal door. A lower gauge will make stronger and more durable doors.

For a quick check, see these standard sizes:

14-gauge: about 1.6 mm

16-gauge: about 1.3 mm

18-gauge: about 1.2 mm

20-gauge: about 0.9 mm

 

It’s crucial to match the gauge to your specific use. High-traffic entries, for instance, require thicker steel for durability, while interior closets can make do with thinner sheets. The same principle applies to fire-rated doors, which can range from 14 to 22 gauge depending on the desired fire resistance.