USPS Flat Rate Box Sizes

What are USPS Flat Rate Boxes?

USPS Flat Rate Boxes are boxes with flat rates, no matter what the weight of the package is. If you’re small items that are heavy, Flat Rate Boxes are going to be your best option. Having a bulk supply of these boxes can help your operations save money and operate smoothly.

How Much Are USPS Flat Rate Boxes?

See the table below for a preview of the cost depending upon the size.

The following rates are based on pricing from September 3, 2019.

TypeSizePrice
Letter Envelope12 1/2" x 9 1/2"6.95
Gift Card Envelopes10" x 7"6.95
Window Envelopes10" x 6"6.95
Small Envelopes10" x 6"6.95
Padded Envelopes12 1/2" x 9 1/2"7.55
Legal Envelopes15" x 9 1/2"7.25
Small Box8 11/16" x 5 7/16" x 1 3/4"7.50
Medium Boxes11 1/4" x 8 3/4" x 6" or 14" x 12" x 3 1/2"12.80
Large Box12-1/4" x 12-1/4" x 6" or 24-1/16" x 11-7/8" x 3-1/8"17.60
APO/FPO Box12-1/4" x 12-1/4" x 6"16.10
Large Board Game Box23 11/16" x 11 3/4" x 3"17.60