USPS Priority Mail Flat Rate Boxes can be a shipping wonder for your business. “If possible, it is sent.” Anything that can fit in one of the USPS priority mail flat rate boxes will be shipped anywhere in the country for a flat rate. This only applies to flat rate mailboxes, which you can get for free at any post office. You can also order them online and have them delivered to your home or business. Flat rate boxes come in three different sizes, small, medium, and large. The medium size has two different shapes to fit different shaped products. Oh yeah, and they also have a flat rate envelope that will get anywhere in the country in 2-3 days.

So the question is how does the post office maintain a flat rate regardless of weight?

Priority Mail Flat Rate Mailboxes are classified according to volume. The post office buys space on an airplane and charges for space in its trucks based solely on the volume of the box. As long as the box weighs less than 70 pounds, the rate will not change. You can get in trouble if you try to pack too much in the boxes and warp the shape and size.

The space that the post office buys is actually bought on FedEx planes. This is how priority mail can reach almost anywhere in 2-3 days. Priority Mail is the fastest service that is not guaranteed overnight service. Priority mail reaches more than 90% of the US in 2 days. And you will always spend the night within a certain radius of your own post office.

Because the post office buys space based on volume, it has also opened up new ways to earn rates. If you ship by priority mail without using the flat rate boxes, your rates will be determined in the same way as UPS Ground. The first factor that determines the rate is the area which is based on the distance from the origin. The second factor is weight. Dimensions can also be a determining factor if the dimensional weight is greater than the actual weight. But with the specific spaces purchased by the post office, you can get a pricing structure based on the volume of your packages.

This is a fairly new concept and is not beneficial to all senders or shipments. The real advantage will come with any package that is less than a cubic foot in volume. Cubic price levels are based on volume and zones. To use this level, packages must weigh less than 20 pounds.

If you ship packages that meet this volume requirement, you can get a special price tier. Depending on the exact volume and zone you’re shipping, any package under 10 pounds should get a better rate than UPS or FedEx Ground. Depending on your discount with UPS or FedEx, it is actually possible to save money on shipping with USPS priority mail up to 20 pounds. And it is a faster service.

If you are interested in priority mail services, including priority mail flat rate mailboxes, please visit your local post office. Or you can visit http://www.usps.com to request a free starter kit. Take an in-depth look at your current rates versus priority mail to find out when and where to use priority mail services. Or contact a shipping consultant to help you perform this analysis.