The service allows a maximum weight of 70 lbs. Priority Mail Flat Rate is a 1 to 3-day shipping service provided by the USPS that features one flat rate for delivery of a box or envelope. USPS Flat Rate Boxes are boxes with flat postage rates, no matter how heavy the box is. The following article can find more details about the USPS Priority Mail Flat Rate options' sizes and prices. This is a great way to prepare for peak shipping. The premise is that you choose the right box size according to your needs. Using a USPS Flat Rate Box can cut your shipping costs by 50%. If you are shipping heavy, small items, Flat Rate Boxes are the best bang-for-your-buck option. Flat rate pricing eliminates the need to weigh packages or calculate shipping fees, as long as the parcel weighs less than 70 lbs. Priority Mail Flat Rate is a 1 to 3-day shipping service provided by the USPS that features one flat rate for delivery of a package or envelope to its destination.

The lightweight American Express enjoys a considerable discount, and the express delivery fee is very cheap.

The United States Postal Service has the largest civilian fleet globally and handles more than 16 billion letters worldwide each year. USPS is an independent agency of the United States Federal Government.

Usps flat rate box dimensions