2023 USPS Flat Rate Shipping Guide: Boxes, Envelopes and Pricing

Let’s face it: shipping can get very complicated. There are many variables at play, such as different carriers, service levels, fees and charges. When you add in changing customer expectations and the need to operate at a profit, it’s enough to make your head spin.

USPS flat rate boxes and flat rate envelopes were created to make shipping simple and efficient. They can also provide great value, but it’s important to realize that USPS flat rate shipping is not a one-size-fits-all solution.

This article will explain how it works so that you can make an informed decision around using USPS flat rate shipping for your business. We’ll explore its many benefits, various packaging options, the rates and delivery speeds for USPS flat rate envelopes and boxes, as well as the types of products that are often shipped in flat rate boxes.

What is USPS Priority Mail® Flat Rate?

USPS Priority Mail and Priority Mail Express services provide a simple, economical way to ship packages quickly, to any destination in the U.S. Ultimately, the price is determined by the package you use, not its weight or the distance to its destination. To qualify for Priority Mail flat rates, you must use branded USPS flat rate packaging that is provided free of charge. You can choose from three different envelope sizes and seven various box sizes.

You pay one flat rate to send a standard-sized package or envelope weighing less than 70 lbs. The delivery will take 1-3 days. USPS flat rate packaging is ideal for shipping small items from coffee mugs to clothing and shoes, computers, basketballs and small appliances. There are even special boxes for shipping board games or sending gifts to service members on military bases.

What are the advantages of USPS flat rate shipping?

There are many good reasons to use USPS flat rate shipping. Advantages include:

  • Easy to use: Flat rate shipping is a no-brainer: there’s no need to weigh or measure every package, and there are no complicated calculations. If an item weighs less than 70 lbs. and fits into a flat rate envelope or box, it ships anywhere in the U.S. for one low price.
  • Free packaging: You can get flat rate packaging free of charge at your local post office or order online from the Postal Store. USPS flat rate envelopes are offered in packs of 10 and boxes are available in packs or 10 or 25. Forever prepaid boxes and envelopes are also available. Although you’ll still need to purchase tape, peanuts and bubble wrap, the savings of at least one dollar per shipment add up quickly.
  • Predictable costs: No more worries about overspending on shipping. When a customer orders an item, you always know exactly what it costs to ship.
  • Fast delivery: Your package will arrive in one to three days. Plus, Priority Mail Express includes a money-back guarantee if your parcel doesn’t arrive by the guaranteed delivery date.
  • No surcharges: There are no add-on costs such as fuel surcharges, residential or Saturday delivery surcharges that are common with other services.
  • Deliverability: You can ship to virtually anywhere in the U.S.— including Alaska, Hawaii, Puerto Rico, the U.S. Virgin Islands and Guam—plus Post Office boxes, military bases and embassies.
  • Free tracking and insurance: Tracking and up to $100 in insurance are included at no extra cost.
  • Free pickup: Your mail carrier will pick up your outbound packages at no cost.
  • Security: The USPS is legally authorized to place packages in your mailbox: other carriers cannot. In some cases, USPS may attempt to re-deliver a large package rather than leave it out in the open where it could easily be stolen.
  • Extra services: Extra insurance, proof of mailing, signature confirmation and more are available for an additional fee.
  • Label delivery: No printer? No problem. If in doubt, call your post office or refer to the complete list of restricted items on the USPS web site.