22″ x 18″ x 15″ for boxes 18 x 18 for envelopes or poly mailers maximum weight:

Smallest box usps will ship. The priority mail flat rate® small box is about the same size and shape as three stacked dvd cases. 8 5/8″ x 5 3/8″ x 1 5/8″ brochures. A second postage rate increase from usps 2021 for postage purchased at the post office, the rate for a first class mail letter (1 oz.) will increase by 3 cents from $0.55 to.

At least 3 inches high x 6 inches long x 1/4 inch thick. What is the smallest package usps will ship? Lettersize pieces have a maximum size of 11.5″x6.125″ and cannot be more than 0.007″ thick.

12 1⁄4″ x 12 1⁄4″ x 6″. Usps small flat rate box dimensions: Usps flat rate boxes are boxes with flat rates, no matter what the weight of the package is.

If the piece is larger than that or is not rectangular, then it would need to ship as a package and. What are usps flat rate boxes? Small — small boxes measure 16” x 10” x 10”.

8 11/16″ x 5 7/16″ x 1 3/4″ inside: According to the usps postal explorer, the minimum package size is at least 6 inches in length, 3 inches in height, and 1/4 of an inch in thickness. Anybody know what's the smallest box size the usps will ship?

This rule applies for any usps mail class you decide to ship in. Boxes come in three sizes: $8.45 medium flat rate box (top loading) dimensions: