January 9, 2024 - To ship with USPS Flat Rate, you need to use USPS Flat Rate boxes. Flat Rate boxes come in three main sizes: small, medium, and large.

1 week ago - The listed exterior is 12¼ inches square, but items over 11¾ inches on any side won't fit cleanly. Sellers packing close to the size limit — framed prints, artwork, certain electronics — find out the hard way.

What Sizes Are Available? Across the U.S. Postal Service, PO Boxes are available in 5 sizes.

Use our Priority Mail Flat Rate Envelopes or Boxes that come in standard sizes so you don't have to worry about measuring them.

The Priority Mail® Top-Loading Large Box is a rectangular–shaped box that accommodates a variety of items such as clothing, books, and hats. This item ships in a pack of 10 or 25 boxes.

March 1, 2026 - USPS offers free Priority Mail Flat Rate boxes in Small (8-11/16" x 5-7/16" x 1-3/4"), Medium (11-1/4" x 8-3/4" x 6" or 14-1/8" x 12" x 3-1/2"), and Large (12-1/4" x 12" x 6"), all up to 70 lbs.

The Priority Mail Flat Rate® Medium Box is an easy way to ship featuring predetermined rates regardless of weight (domestically) or destination. This item ships in single, or a pack of 10 or 25 boxes.

February 11, 2026 - Sold in packs of 25, each box measures 8 ¾” x 5 9/16” x 7/8”, making them perfectly sized to hold one or two DVDs or CDs. These boxes, along with a wide range of other shipping supplies, can be delivered to your business at no additional ...

3 weeks ago - Shop our selection of Shipping Supplies on the USPS.com Postal Store

March 20, 2026 - The most commonly used Flat Rate formats are the Flat Rate Envelope, Legal Flat Rate Envelope, Padded Flat Rate Envelope, Small Flat Rate Box, two Medium Flat Rate Boxes, and the Large Flat Rate Box. USPS also offers additional non-Flat-Rate Priority Mail and Priority Mail Express packaging in other shapes and sizes.

August 28, 2025 - USPS boxes come in small, medium, and large sizes with different dimensions and costs. Learn about USPS's different boxes here.

November 10, 2023 - When determining your package size, you may need to know the package's girth. Girth: The width and height of a package doubled and added together. Some domestic shipping supplies are offered for free through the USPS. Click on the following options to order free boxes:

September 4, 2025 - These flat rate boxes are available in three different sizes such as small, medium, and large. This flat rate packaging is also available in envelopes, padded envelopes, board game boxes, and military shipping boxes (APO/DPO).

If you have a large, lightweight ... price depending on the class of mail and additional factors. ... Parcels going to a domestic location may not measure more than 108 inches in length and girth combined. USPS Ground Advantage® mailpieces are an exception; they may not measure ...

Most Post Offices have 5 PO Box sizes, depending on availability*. Sizes range from extra small (XS – Size 1) to extra large (XL – Size 5). Choose your PO Box size based on the type of mail (letter-sized mail or packages) and how much mail ...

January 5, 2026 - USPS flat rate boxes are free to order, but they can only be used with Priority Mail Flat Rate. They work best for heavy, compact shipments because the price stays the same up to 70 lbs, regardless of destination. In this guide, you’ll find the current USPS flat rate box sizes, prices, and when flat rate is cheaper than using your own box.

The table below shows options for different Priority Mail Boxes and Envelopes, along with dimensions, online postage pricing and ... Order USPS Supplies in Bulk!

3 weeks ago - Here are some examples that illustrate how Flat Rate Packaging can be more expensive: Medium Flat Rate Box 1 dimensions: 11 x 8.5 x 5.5 inches · Medium Flat Rate Box 2 dimensions: 14 x 12 x 3.5 inches · If you used your own box that was the ...

August 8, 2023 - There are two sizes · Top loading box B1: 12.25″ x 10.5″ x 5.5″ · Side loading box B2: 14.5″ x 3″ 16.25″ · 20 lb weight limit for domestic shipments · Domestic Priority delivery within 1-3 business days · For more information ...

June 26, 2025 - According to USPS, the minimum package size is at least 6 inches in length, 3 inches in height, 1/4 of an inch in thickness, or 6 x 3 x 0.25. This regulation means that the size and height of your package box should be at least 6 inches in length ...