Shipping shoes and heavy items: size, weight, and dimensional weight.

For USPS Ground Advantage, the Domestic Mail Manual allows cubic pricing for a piece that measures 1 cubic foot or less, weighs 20 pounds or less, and has a longest dimension of 22 inches or less. Rolls and tubes are excluded. To find the cubic size, measure length, width, and height, round each down to the nearest quarter inch, multiply them, and divide by 1,728 cubic inches. Prices come in ten tiers from 0.10 to 1.00 cubic foot.¹

As an illustration with sample numbers, a shoe box measuring 13 by 8 by 5 inches is 520 cubic inches, which is about 0.30 cubic foot, under the 1 cubic foot line. A retail shoe box and a larger outer shipping box give different numbers, so measure the package you will actually mail. The tier prices are in USPS's price list, so check the USPS price calculator² or the eBay label price rather than a table here.

For Ground Advantage, dimensional weight applies to parcels addressed to zones 1 through 9 that exceed 1 cubic foot. Postage is based on the greater of the actual weight and the dimensional weight. For a rectangular parcel, round each dimension up to the nearest whole inch and multiply them. If the result is more than 1,728 cubic inches, divide by 139 and round up to get the dimensional weight in pounds. If the dimensional weight is over 70 pounds, the 70 pound price applies.¹ The Priority Mail section of the manual describes the same threshold and divisor for rectangular parcels.³

As an illustration with sample numbers, a box measuring 20 by 16 by 12 inches is 3,840 cubic inches. Divided by 139, that is about 27.6, which rounds up to 28 pounds of dimensional weight. If the item inside weighs 6 pounds, the parcel is priced as the greater figure, 28 pounds. Use this to test boots, coats in boxes, and bulky packaging. The manual has separate formulas for nonrectangular parcels, which this guide does not reproduce.

UPS and FedEx publish their own dimensional weight rules and divisors, and rates on a negotiated account can differ. This guide did not confirm either carrier's current figures, so check the carrier before using the 139 divisor for anything other than USPS.

The manual lists these thresholds for Ground Advantage:¹

• Pricing runs from 1 through 70 pounds.
• Nonstandard fees apply to pieces more than 22 inches up to 30 inches long, more than 30 inches long, or more than 2 cubic feet (3,456 cubic inches).
• Oversized pricing applies to pieces over 108 inches but not over 130 inches in combined length and girth. The service page gives 130 inches of combined length and girth as the size limit.⁴
• The mailer must give accurate dimensions, and omitted or inaccurate dimensions trigger a Dimension Noncompliance fee.

Dollar amounts for these fees are in USPS Notice 123 and are not listed here.

The manual says heavy items must be braced and cushioned so they do not damage other mail, and that a box must keep its shape without bending, folding, or collapsing.⁵ Choose a box that holds its shape under the load. See the shipping supplies guide for boxes and wrap, and the fragile items guide if the item is also breakable.

For heavy or bulky items, the label can cost more than expected. Strooply can estimate shipping cost before you have the item in hand and shows profit after fees and shipping. The estimate is not a carrier quote. Test a price in the eBay fee calculator, and see the shipping overview for other services.