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. Step One: Obtain a flat rate shipping box or envelope from your shipping carrier.

To take advantage of flat rate shipping costs, simply follow these three simple steps. UPS is the exception to the rule: it offers shippers the option to purchase branded packaging or use their own packaging. USPS and FedEx require that you use their flat rate packaging. If flat rates are included in your negotiated UPS and/or FedEx rate card, you can simply import them into PitneyShip™ or PitneyShip™ Pro to see a comparison of the available rates and delivery dates. If you want to know whether flat rate shipping is the best option for your package, multi-carrier shipping software can help you make the right decision. All are limited to domestic shipping, although USPS priority flat rate mail offers shipping to military bases and embassies overseas. 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.

Usps priority flat rate envelope