Wire Spacing = Wire Diameter + Opening Size
Opening Size (O) = Wire Spacing - Wire Diameter
Wire Diameter (D) = Wire Spacing - Opening Size
Mesh count (M) = 1 / (O+D)
Opening (O) = (1-DM) / M
Open Area % = (OM)2 x 100 or [O/(O+D)]2 x 100 or (1 - MD)2 x 100