A wire gauge, either British or American, can be used to measure either wire or metal sheets. To do this follow these steps:
Step 1 – Select gauge system
Select a gauge that uses either the British Standard Wire Gauge or American Wire Gauge system.
Step 2 – Fit into precise diameter cut-out
To measure the wire, slide it into a slot on the gauge which looks to be the same width. Keep moving the wire around the gauge until the wire fits into the slot with a tight fit. The number next to the slot will state what size it is, for example 16 gauge.