Corrugated or folding carton?

Almost every box is one or the other, and the choice decides which standard, which style codes and which board you are working with. It is usually obvious once you know what separates them.

The short answer

• Corrugated — fluted board, a wavy layer glued between liners. Stiff, protective, thick. Shipping boxes, mailers, trays. Styles are numbered by FEFCO, four digits: 0201.
• Folding carton — solid cartonboard, no flutes. Thin, smooth, prints beautifully. Cereal boxes, cosmetics, pharmaceuticals. Styles are numbered by ECMA, dotted: A20.20.03.01.

Thickness is the practical difference

Corrugated board is measured in millimetres — B flute is about 3 mm, E flute about 1.5 mm. Cartonboard is measured in microns or gsm, and a typical 350 gsm board is around 0.45 mm. That is roughly seven times thinner, and it changes the drawing: every allowance for board thickness shrinks with it. See flutes and calipers.

Which one do you need?

Ask what the box has to survive.

• Posted, couriered or stacked on a pallet — corrugated. It is the only one of the two with meaningful crush resistance.
• Sitting on a shelf, handled by a customer, carrying fine print — folding carton. A retail carton in corrugated looks and feels wrong, and the flutes show through the print.
• Both — a folding carton inside a corrugated shipper is entirely normal, and the two are designed separately.

Styles do not translate

There is no FEFCO equivalent of a reverse tuck end, and no ECMA equivalent of a regular slotted container. The constructions suit their materials: a slotted case relies on flaps meeting across a thick board, a tuck end relies on a tongue slipping inside a thin one. If you find yourself hunting for the "FEFCO version" of a carton style, you are probably on the wrong material.

Not sure which style within either? Try the style finder.