C flute vs BC double wall: side-by-side numbers

BC double wall is 80% thicker than C flute (0.281 vs 0.156 in nominal). At the same ECT, the McKee formula rates a BC double wall box 34% stronger in compression; the trade is in size, crush resistance and print surface.

Side by side

BC double wall is 0.125 in thicker than C flute. On a 12 × 10 × 8 in box that makes the outside 0.25 in longer and wider and 0.38 in deeper, and at the same ECT the McKee estimate for C flute is 75% of the BC double wall figure.

	C flute	BC double wall
Walls	single	double
Nominal caliper, in	0.1563	0.2813
Flutes per foot	39	—
OD added to L and W, in	0.313	0.563
OD added to depth, in	0.469	0.844
McKee strength index, same ECT	39.5	53

Same box, both boards

Inside, in	BCT at 44 ECT, C	BCT at 44 ECT, BC	Boxes per pallet, C	Boxes per pallet, BC
10 × 8 × 6	613	822	144	119
16 × 12 × 10	764	1,025	40	40
24 × 18 × 18	936	1,255	6	6

44 ECT is used on both sides only to isolate thickness; in practice the two boards are made to different grades. Pallet: 48 × 40, loaded to 60 in, column stacked.

Where each fits

C flute

Thicker than B, so stronger in McKee at the same ECT
Fewer flutes per foot than B, so slightly less crush and puncture resistance
Print surface is fine for simple marks; fine graphics prefer finer flutes

BC double wall

Nearly twice the caliper of C, so much stronger in McKee at the same ECT
Heavier and bulkier: more board weight and larger outside dimensions
The B ply on one face gives a better print or wear surface

More comparisons

Sources

Foster, G. (1997). "Boxes, Corrugated." In Brody & Marsh (eds.), The Wiley Encyclopedia of Packaging Technology, 2nd ed. Wiley. ISBN 0-471-06397-5 (table reproduced in Wikipedia, "Corrugated fiberboard")
Packaging Corporation of America: Profiles with a purpose
McKee, Gander & Wachuta (1963), Paperboard Packaging 48(8)

Last reviewed 2026-10-27. See all sources and how Packgent computes.