
There are various package types and sizes to choose from as well, and this packaging is also free. There is no cost for an envelope when using flat rate shipping-you’ll pay only the small flat rate cost, the envelope itself is free.

The major carriers’ flat rate options are called USPS Priority Mail® and FedEx One Rate®. Up to a certain weight, there is valuable predictability in flat rate shipping, meaning it virtually eliminates the need to weigh packages if the contents weigh less than 70lbs for USPS or 50lbs for UPS and FedEx.


As a shipping method, flat rate is preferred by many shippers for its convenience, although it may not always be the lowest-cost shipping option available. The larger the flat rate box, the more it will cost to ship. The carriers charge a single fixed rate based on the size of a box or envelope rather than its weight. It’s a service offered by the major shipping carriers.
