Dimensions / Industrial & logistics / Corrugated boxes / Single wall
A single-wall corrugated box is one corrugated medium glued between two flat facings (NMFC Item 222-6). Its common grade, 200# burst or 32 ECT, may carry 65 lb of box and contents at up to 75 in of outside length + width + depth under rail Rule 41; the seven single-wall grades run from 125# or 23 ECT (20 lb, 40 in) to 350# or 55 ECT (120 lb, 105 in). In C flute, 200# board is .159 in thick (Walmart’s caliper chart). Sizes are inside length × width × depth: Uline’s 16 × 16 × 16 in box measures 16 3/8 × 16 3/8 × 16 5/8 in outside. Parcel guidance is lower: Uline cites UPS at 40 lbs for 200# and 30 lbs for 32 ECT.
| Box and contents, max, 200# or 32 ECT | Outside length + width + depth, max | C-flute board, 200# |
|---|---|---|
| 65lb29.5 kg | 75in1,905 mm | .159in.408 cm |
Sources: Rule 41, Walmart caliper chart. Checked October 2026.
Uline’s 16 × 16 × 16 in box, measured outside, and the 200# or 32 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.
416 + 416 + 422 = 1254 mm, within 1905 mm, and 20 kg is within the 29.5 kg limit of this grade.
Filled in: Rule 41’s 200# or 32 ECT row, 65 lb (29.5 kg) and 75 in (1,905 mm), and Uline’s 16 × 16 × 16 in box measured outside. A parcel carrier may allow less: Uline cites UPS at 40 lbs for 200#.
Boxes of 416 × 416 mm fit 4 per layer on the 1219 × 1016 mm deck without overhang, and 422 mm boxes go 3 high under 1778 mm with the 141 mm pallet: 12 a pallet, enough for 12.
CHEP’s 48 × 40 in pallet, 141 mm tall, and FedEx Express Freight’s 70 in skid height are filled in. FedEx Freight: overhang can reduce compression strength by as much as 32 percent.
Loose and upright, the boxes go 70 per layer and 5 high in 2393 mm: 350, enough for your 300, and 6000 kg is within the 28380 kg payload.
Triton’s 20 ft, loaded loose with every box upright. The size limit in Rule 41 adds outside dimensions, the same ones this check packs.
Shipping in single-wall cartons? Photograph a packed carton, mark its outside size and gross weight in SizeMarker and send it with the packing list.
Mark a photoA box may meet either the burst test (psi) or the 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 |
|---|---|---|
| 125# burst or 23 ECT | 20 lb9.1 kg | 40 in1,016 mm |
| 150# burst or 26 ECT | 35 lb15.9 kg | 50 in1,270 mm |
| 175# burst or 29 ECT | 50 lb22.7 kg | 60 in1,524 mm |
| 200# burst or 32 ECTThe common grade | 65 lb29.5 kg | 75 in1,905 mm |
| 250# burst or 40 ECT | 80 lb36.3 kg | 85 in2,159 mm |
| 275# burst or 44 ECT | 95 lb43.1 kg | 95 in2,413 mm |
| 350# burst or 55 ECT | 120 lb54.4 kg | 105 in2,667 mm |
Sources: Rule 41
| Item | What the source says |
|---|---|
| BuildNMFC Item 222-6 | One corrugated inner medium glued between two flat facings |
| Other nameFibre Box Association | Also known as Double Face |
| C flute, 200#Walmart caliper chart | .159 in (.408 cm) |
| C flute, 125# to 350#Walmart caliper chart | .151 in to .181 in |
| B and A flute, 200#Walmart caliper chart | B .121 in (.310 cm); A .201 in (.515 cm) |
| Grades in FBA-funded testsRIT study, 2021 | 32 and 44 ECT, single wall C flute, the two commonly used grades |
| 200 lb. test vs 32 ECTUline | 200 lb. test refers to bursting strength, while 32 ECT refers to stacking strength |
| Weight of the boxUline | 32 ECT boxes are up to 19% lighter than 200 lb. test |
| Parcel guidanceUline, citing UPS | 30 lbs. for 32 ECT; 40 lbs. for 200 lb.; 65 lbs. for 275 lb. |
| Manufacturer’s jointRule 41, Section 5 | Lapped not less than 1 1/4 inches; if stapled, staples not more than 2 1/2 inches apart |
Sources: NMFC Item 222 · Fibre Box Association · Walmart caliper chart · FBA pallet pattern study · Uline (FAQ) · Uline (S-21546) · Rule 41
Sizes are inside length × width × depth unless marked outside. All from distributors’ listings.
| Box | Size | Grade; weight or rating |
|---|---|---|
| Uline S-4166 | 16 x 16 x 16 inOutside 16 3/8 x 16 3/8 x 16 5/8 in | 200 lb. test; 1.70 lbs |
| Uline S-21546 | 18 x 16 x 12 inOutside 18 3/8 x 16 3/8 x 12 5/8 in | 32 ECT; 1.33 lbs |
| Uline S-4133, tall | 6 x 6 x 18 inOutside 6 3/8 x 6 3/8 x 18 5/8 in | 200 lb. test, C flute; 0.52 lbs |
| Global Industrial WBB68688 | 14 x 10 x 10 in | 200#/ECT-32; 65 lbs capacity |
| Global Industrial WBB2311335 | 24 x 18 x 18 in4.5 cubic feet | 200#/ECT-32; 65 lbs capacity |
| Lavex 442BRK141436 | 14 x 14 x 36 in | ECT 32, C flute |
| Staples 121012 | 12 x 10 x 12 in | 32 ECT, C flute; holds up to 65 lbs |
Sources: Uline (S-4166) · Uline (S-21546) · Uline (S-4133) · Global Industrial (14 x 10 x 10) · Global Industrial (24 x 18 x 18) · Lavex (single wall) · Staples (32 ECT)
| Rule or figure | What it says |
|---|---|
| Listed sizesUline | Always inside dimensions; length is the longest side that has a flap |
| Inside to outsidePresident Container | A single-wall C-flute board of about 5/32 inch makes each outer dimension about 5/16 inch larger |
| Uline S-4166 outside, in mmOur conversion | 416 × 416 × 422 mm |
| OverhangFedEx Freight | Can reduce compression strength by as much as 32 percent |
| Skid heightFedEx Express Freight | Over 70 in needs prior approval1,778 mm, our conversion |
| CHEP B4840A palletCHEP | 1219 × 1016 × 141 mm48 × 40 in |
| S-4166 on that palletOur calculation | 4 a layer, 3 layers under 1,778 mm: 12 |
| 20 ft insideTriton | 5,898 × 2,352 × 2,393 mm; 28,380 kg payload |
| S-4166 in that 20 ft, looseOur calculation | 70 a layer, 5 layers: 350 |
Sources: Uline (measuring) · President Container · FedEx Freight · FedEx (How to Pack) · CHEP (B4840A) · Triton (20ft)
A box of one corrugated medium glued between two flat facings (NMFC Item 222-6), which the Fibre Box Association also calls Double Face. It is made in seven grades, from 125# or 23 ECT up to 350# or 55 ECT (Rule 41).
Under rail Rule 41, a 200# or 32 ECT box may carry 65 lb of box and contents with outside length + width + depth up to 75 in; the 350# or 55 ECT grade takes 120 lb and 105 in. For parcels Uline cites UPS lower: 40 lbs for 200 lb. test and 30 lbs for 32 ECT.
In Walmart’s industry caliper chart, 200# board is .121 in in B flute, .159 in in C flute and .201 in in A flute; C flute runs from .151 in at 125# to .181 in at 350#.
200 lb. test refers to bursting strength, while 32 ECT refers to stacking strength (Uline). Rule 41 accepts either one for the 65 lb, 75 in row, and 32 ECT boxes are up to 19% lighter than 200 lb. test.
Inside: Uline lists inside dimensions, with the length the longest side that has a flap. Its 16 x 16 x 16 in box is 16 3/8 x 16 3/8 x 16 5/8 in outside, and the Rule 41 size limit adds outside dimensions.
It depends on the outside size. Uline’s 16 × 16 × 16 in box, 416 × 416 × 422 mm outside, fits 4 a layer on a 48 × 40 in CHEP pallet without overhang, and 3 layers stay under FedEx Express Freight’s 70 in: 12, by our calculation.
Buyers of light goods ask for the carton’s outside size, its gross weight and the 200# or 32 ECT grade on the certificate, since a courier and a freight carrier allow different weights. 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.
