Dimensions / Industrial & logistics / Corrugated boxes / Double wall
A double-wall corrugated box has three flat facings and two corrugated mediums (NMFC Item 222-6). Its common grade, 275# burst or 48 ECT, may carry 100 lb of box and contents at up to 95 in of outside length + width + depth under rail Rule 41; the six double-wall grades run from 200# or 42 ECT (80 lb, 85 in) to 600# or 82 ECT (180 lb, 120 in). At 275#, B/C board is .264 in thick and A/C .344 in (Walmart’s caliper chart). Uline’s 24 x 24 x 24 in double-wall box measures 24 3/4 x 24 3/4 x 25 in outside. FedEx: use double-wall boxes for heavier items.
| Box and contents, max, 275# or 48 ECT | Outside length + width + depth, max | B/C board, 275# |
|---|---|---|
| 100lb45.4 kg | 95in2,413 mm | .264in.677 cm |
Sources: Rule 41, Walmart caliper chart. Checked October 2026.
Uline’s 24 x 24 x 24 in double-wall box, measured outside, and the 275# or 48 ECT limits are filled in. Enter your gross weight; each check uses the numbers in the tables on this page.
Sizes in millimetres, weights in kilograms, the box measured outside (1 in = 25.4 mm, 1 lb = 0.4536 kg). Boxes stand upright, in straight columns.
629 + 629 + 635 = 1893 mm, within 2413 mm, and 35 kg is within the 45.4 kg limit of this grade.
Filled in: Rule 41’s 275# or 48 ECT row, 100 lb (45.4 kg) and 95 in (2,413 mm), and Uline’s 24 × 24 × 24 in double-wall box, 24 3/4 × 24 3/4 × 25 in outside.
Boxes of 629 × 629 mm fit 1 per layer on the 1219 × 1016 mm deck without overhang, and 635 mm boxes go 2 high under 1778 mm with the 141 mm pallet: 2 a pallet, enough for 2.
Side by side two of these boxes take 1,258 mm, more than the 1,219 mm pallet, so a layer holds one. Stack in columns: FBA’s study lost 49 – 54% of compression strength interlocked.
Loose and upright, the boxes go 27 per layer and 3 high in 2393 mm: 81, enough for your 80, and 2800 kg is within the 28380 kg payload.
A layer in Triton’s 20 ft takes 9 along by 3 across of the 629 mm boxes, 3 layers high, by our calculation.
Exporting heavy goods in double-wall cartons? Photograph one packed, mark its outside size, board and weight in SizeMarker and send it with the packing list.
Mark a photoBurst test (psi) or edge crush test (ECT, lb per inch); size is the outside length, width and depth added. Metric in grey is our conversion.
| Grade | Box and contents, max | L + W + D, max |
|---|---|---|
| 200# burst or 42 ECT | 80 lb36.3 kg | 85 in2,159 mm |
| 275# burst or 48 ECTThe common grade; Rule 41, Section 3 | 100 lb45.4 kg | 95 in2,413 mm |
| 350# burst or 51 ECT | 120 lb54.4 kg | 105 in2,667 mm |
| 400# burst or 61 ECT | 140 lb63.5 kg | 110 in2,794 mm |
| 500# burst or 71 ECT | 160 lb72.6 kg | 115 in2,921 mm |
| 600# burst or 82 ECT | 180 lb81.6 kg | 120 in3,048 mm |
Sources: Rule 41
| Item | What the source says |
|---|---|
| BuildNMFC Item 222-6 | Three flat facings and two intermediate corrugated mediums |
| Build, in the FBA’s wordsFibre Box Association | Three sheets of linerboard with two mediums in between |
| B/C board, 200# to 600#Walmart caliper chart | .258 in to .308 in; 275#: .264 in (.677 cm) |
| A/C board, 200# to 600#Walmart caliper chart | .338 in to .388 in; 275#: .344 in (.882 cm) |
| For single wall, C flute 200#Walmart caliper chart | .159 in |
| When to use itFedEx | Use double-wall boxes for heavier items |
| Against single wallUline | Double the protection of a 200 lb. test box; use when extra stacking strength is needed |
| Glass over 65 lb grossNMFC Item 222-2 | Inner containers up to one gallon may ship in doublewall testing not less than 275 pounds or 48 ECT; gross weight up to 100 pounds, inside dimensions up to 100 inches |
| Parcel guidanceUline, citing UPS | 200#: 60 lbs; 275#: 80 lbs; 350#: 100 lbs; 500#: 140 lbs |
Sources: NMFC Item 222 · Fibre Box Association · Walmart caliper chart · FedEx (How to Pack) · Uline (S-15062) · Uline (S-4740)
Inside length × width × depth unless marked outside. All from distributors’ listings.
| Box | Size | Grade; weight or rating |
|---|---|---|
| Uline S-4740 | 24 x 24 x 24 inOutside 24 3/4 x 24 3/4 x 25 in | 275 lb. test double wall; 6.20 lbs; UPS 80 lbs |
| Uline S-15062 | 48 x 24 x 12 inOutside 48 3/4 x 24 3/4 x 13 in | 275 lb. test double wall; 7 lbs; UPS 80 lbs |
| Global Industrial WBB39762 | 18 x 18 x 18 in | 275# DW/ECT-48 |
| Baytec 8HD242412DW | 24 x 24 x 12 in | 275# D.W./ECT-48; 48 lb a bundle of 10 |
| Lavex 442BOX302412HDDW | 30 x 24 x 12 in | ECT 48; rated to hold up to 80 lb |
| Uline S-4740 outside, in mmOur conversion | 629 × 629 × 635 mm | — |
Sources: Uline (S-4740) · Uline (S-15062) · Global Industrial (double wall) · Baytec · Lavex (double wall)
| Rule or figure | What it says |
|---|---|
| Column vs interlockFBA study, Table 12 | Columnar aligned: 12 – 20% less compression strength; interlocked: 49 – 54% |
| Palletized freightFedEx Freight | Column-stack loads |
| InterlockingYRC Freight | Can reduce top-to-bottom compression strength up to 50 percent |
| CHEP B4840A palletCHEP | 1219 × 1016 × 141 mm48 × 40 in |
| Two S-4740 side by sideOur calculation | 1,258 mm, more than the 1,219 mm pallet: one a layer |
| Skid heightFedEx Express Freight | Over 70 in needs prior approval1,778 mm, our conversion |
| 20 ft insideTriton | 5,898 × 2,352 × 2,393 mm; 28,380 kg payload |
| S-4740 in that 20 ft, looseOur calculation | 9 along by 3 across, 27 a layer; 3 layers: 81 |
Sources: FBA pallet pattern study · FedEx Freight · YRC Freight · CHEP (B4840A) · FedEx (How to Pack) · Triton (20ft)
A box of three flat facings and two corrugated mediums (NMFC Item 222-6). Rule 41 lists six double-wall grades, from 200# or 42 ECT to 600# or 82 ECT, and the 275# or 48 ECT grade is the common one.
Under rail Rule 41, 275# or 48 ECT allows 100 lb of box and contents with outside length + width + depth up to 95 in, and 600# or 82 ECT allows 180 lb and 120 in. For parcels Uline cites UPS at 80 lbs for 275# and 140 lbs for 500#.
At 275#, B/C board is .264 in (.677 cm) and A/C .344 in (.882 cm) in Walmart’s caliper chart, against .159 in for single-wall C flute at 200#.
For heavier items, says FedEx, and when extra stacking strength is needed, says Uline. Under NMFC Item 222-2, glass in inner containers up to one gallon, over 65 lb gross, may ship in double wall testing not less than 275 pounds or 48 ECT.
In columns: FedEx Freight says column-stack loads, and in the FBA study interlocked boxes lost 49 – 54% of their compression strength against 12 – 20% aligned. Measure outside: two of Uline’s 24 in boxes take 1,258 mm, more than a 1,219 mm pallet.
Buyers of machine parts, tiles or bottled goods ask whether the export carton is double wall, which grade is on its certificate, its outside size and gross weight, and how it stacks on the pallet. Mark the real carton, its board and label on your own product photo in SizeMarker, as in the picture at the top, and send one product card for WhatsApp or WeChat.
