Carton area formula!

Carton area formula!

The formula for calculating the area of flat box is as follows:
Single carton area s = [(length + width) × 2 + 8] × (width + height + 4)
Double carton area s = [(length + width + 8) × 2] × (width + height + 4)
Note: the unit of length, width, height, 8 and 4 is cm