42 ECT EB double wall: box compression and stacking table

42 ECT EB double wall pairs a 42 lb/in edge crush with a nominal 0.188 in caliper. As an empty 12 × 12 × 12 in box, the simplified McKee formula puts it near 740 lbf of top-to-bottom compression before any allowance for storage or humidity.

Compression, derated for storage time

BCT after storage losses, lbf, 42 ECT EB double wall
Inside size, in	0 days	10 days	30 days	90 days	180 days
8 × 6 × 4	565	356	339	311	282
10 × 8 × 6	641	404	384	352	320
12 × 12 × 12	740	466	444	407	370
14 × 10 × 8	740	466	444	407	370
16 × 12 × 10	799	503	479	439	399
18 × 12 × 12	827	521	496	455	413
18 × 18 × 18	906	571	544	498	453
20 × 16 × 14	906	571	544	498	453
24 × 18 × 18	978	616	587	538	489
24 × 24 × 24	1,046	659	628	575	523

0 days is the McKee estimate itself. Storage losses are Packgent's default assumptions (10 days 37%, 30 days 40%, 90 days 45%, 180 days 50%), not sourced values; edit them in the stacking calculator.

How many high can it stack?

Boxes high, including the bottom one, column stacked for 30 days, before humidity, interlock or overhang losses.

12 × 10 × 8 in, BCT ≈ 708 lbf
Gross weight per box	10 lb	20 lb	30 lb	40 lb	60 lb
Boxes high	43	22	15	11	8

16 × 12 × 10 in, BCT ≈ 799 lbf
Gross weight per box	10 lb	20 lb	30 lb	40 lb	60 lb
Boxes high	48	24	16	12	8

20 × 16 × 12 in, BCT ≈ 906 lbf
Gross weight per box	10 lb	20 lb	30 lb	40 lb	60 lb
Boxes high	55	28	19	14	10

Boxes high = ⌊BCT × (1 − 0.4) ÷ gross weight⌋ + 1. A real stack needs further allowance for humidity, pattern and handling.

Neighbouring grades

Grade	ECT change	BCT change, same flute and size
48 ECT	+6 lb/in	+14%

In McKee, BCT scales directly with ECT, so the percentage change in strength equals the change in ECT.

Freight rule limits

NMFC Item 222 ties each grade to a maximum gross weight and size for LTL shipping. Packgent has not published those limits yet because they could not be checked against the current tariff. See the Item 222 page for status.

Sources

TAPPI T 811: Edgewise compressive strength of corrugated fibreboard (short column test)
McKee, R.C., Gander, J.W. & Wachuta, J.R. (1963). "Compression strength formula for corrugated boxes." Paperboard Packaging 48(8): 149–159
Flute calipers: Foster (1997), Wiley Encyclopedia of Packaging Technology

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