Publication 2 - Packaging for Mailing - Postal Explorer - USPS.com

Containers2-3.22-3.1.3 Solid and CorrugatedFiberboardBox Manufacturer’scertificateA solid and corrugatedfiberboard box isacceptable for all loadtypes up to the weight andsize limits shown in Exhibit 2-3.1.3, unlessotherwise specified. The box grade(bursting strength) of a box is printedwithin the circular or rectangularboxmaker’s certificate (pictured here),which lists the box’s maximum size andgross weight limits for easy and averageloads. The first maximum limit reached foran item to be mailed, whether size or weight,governs the grade of box to be used.Exhibit 2-3.1.3Maximum Weight(Box + Contents, Pounds)Easy orAverage LoadDifficultLoadMaximum Size(Length + Girth,Inches)20 N/A 67 12540 20 100 17565 45 108 20070 65 108 275N/A 70 108 350Box Grade(Bursting Strength,Pounds per Square Inch)2-3.1.4 Wood, Metal, or PlasticA wood, metal, or plastic box is acceptable for all load types. The box’sacceptability depends on its construction, its ability to withstand shock andpressure, and its potential to damage other items.2-3.2 SizeA box used as a mailing container must be large enough to hold the itemsand any surrounding interior cushioning material. If the box is too large andthe items inside the box are inadequately blocked or cushioned, the itemsmight shift in transit. If the box is too small, the cushioning might beineffective protection. In either case, the box or items might get damagedduring handling and mail processing.Publication 2, January 20029