Learn what Priority Mail is, what it does best, and who can save the most by using it for shipping
Finding the lowest prices, fastest delivery times, and best service for your customer shipments can be complicated—especially when carriers offer multiple service options.

Shipping services can be difficult to sort through to find a good fit, and USPS Priority Mail is no different. It includes multiple distinct shipping methods, with their own optimal uses and cost structures.

But if used strategically, USPS Priority Mail offerings can provide you a competitive edge. Here’s how.

What Is USPS Priority Mail?

Priority Mail is the USPS’s top-tier shipping service. It offers faster delivery (one to three business days), along with a host of other benefits, including:

  • Free Package Pickup or Pickup on Demand
  • Up to $50 of insurance coverage for free
  • Free package tracking
  • No additional fees for fuel, residential/rural deliveries, or deliveries on Saturday

Priority Mail can even be used to ship packages to international destinations and overseas US military post offices. Best of all, using Priority Mail doesn’t have to be time consuming or costly; by using eHub’s API and native integrations, it’s possible to save time and reduce shipping costs.

The Priority Mail category breaks down into several distinct shipping methods, each with their own advantages, pricing structure, and specific requirements that have to be met to use:

  • Standard Priority Mail
  • Priority Mail Flat Rate
  • Priority Mail Cubic
  • Priority Mail Regional
  • Priority Mail Express

Standard Priority Mail

This basic option functions similarly to normal shipping, but with the added perks of Priority. You bring your own box, and shipping costs are based on package weight and delivery distance. Despite the similarities, however, there are additional requirements to get the service upgrade:

  • No package larger than 108” in combined length and girth (the length of the longest side, plus the distance around its thickest part)
  • No package weighing more than 70 pounds

Finally, some large, lightweight packages shipped via standard Priority Mail may be subject to additional “dim” charges.

This standard method, though, is the least advantages way to use the program. It’s better service, but it’s also a cost increase. One of the following shipping methods is usually a better fit.

What Is USPS Priority Mail Flat Rate?

Flat Rate is built around specially marked packaging of various types and sizes, each with a prest “flat-rate” cost. If it fits in the box, and the total weight is at most 70 pounds, it ships for the cost of the packaging , regardless of actual weight or distance.


  • Use the USPS-provided packaging
  • Box can be closed properly
  • 70 pound maximum

  • Boxes are provided
  • Easy-to-calculate shipping costs
  • Heavier packages cost the same

  • Cannot use branded packaging
  • No savings for lighter packages
  • Limited packaging options

Special Considerations

  • The USPS provides a variety of flat rate containers to choose from, allowing you to pick the packaging that fits the shipment, and pay accordingly
  • Package rates range from about $7 to $20, depending on the container used
  • “Prepaid Forever” Flat Rate containers function much like forever stamps; purchase the box in advance, and never worry about a flat rate price increase

Optimum Use Cases

Shippers save the most using flat rate when shipping heavier items that fit the box, especially if the package needs to travel a great distance. For smaller items, especially those weighing less than 20 pounds, flat rate may not be an optimal choice.

What Is USPS Priority Mail Cubic?

Cubic offers reduced prices for small packages that weigh less than 20 pounds. Costs are based on package volume, and delivery distance, benefiting small-yet-hefty shipments.


  • Less than 20 pounds
  • .5 cubic feet max volume
  • No side measures more than 18”
  • 50K annual shipment minimum (but see below for a way around this)

  • Heavier packages save up to 50%
  • Branded packaging can be used

  • Packaging not provided
  • Volume calculations required for price
  • Requires high shipping volume (or the right partner)

Special Considerations

Priority Mail is the USPS’s top-tier shipping service. It offers faster delivery (one to three business days), along with a host of other benefits, including:

  • Cubic works best for packages that are roughly shoebox-sized
  • Like Flat-Rate, save more shipping envelopes, bags, and sacks with Cubic Softpack
  • Partnering with a shipping aggregator allows low-volume shippers to qualify

Optimum Use Cases

Priority Mail Cubic is extremely cost-effective for small, heavy packages, especially when they’re traveling a shorter distance.

Most SMBs aware of the program think they can’t get around the 50k shipment minimum. With eHub as a partner, however, you can use cubic since your shipments are combined with the batch we send their way, qualifying them for the program.

Learn how we’ve helped our customers streamline and optimize their shipping programs.

What Is USPS Priority Mail Regional?

According to USPS, Priority Mail Regional “combines the speed and convenience of Priority Mail shipping with zone pricing to reduce costs.” Like flat rate, it uses designated USPS boxes, but prices are based on distance, resulting in discounts for closer destinations.


  • Use provided packaging
  • Doesn’t exeed max weight (15 lbs. for Box A, 20 lbs. for Box B)

  • Closer deliveries = better rates
  • Packaging provided

  • Online-only program
  • Cannot use branded packaging
  • Less useful for longer distances
  • Fewer package size options

Special Considerations

  • Only four box sizes (two each of Box A and Box B)
  • Boxes must be ordered online
  • No softpack option

Optimum Use Cases

Since prices are based solely on distance, regional works best for shipments with higher weights and similar dimensions to cubic, but don’t need to travel far. Fewer benefits for smaller, lighter, or further-traveling packages.

What Is USPS Priority Mail Express?

Express is the USPS’s domestic overnight and second-day service, delivering to most US addresses 365 days a year.


  • Use official Priority Mail Express packaging
  • 70 pound maximum)
  • Combined length and girth doesn’t exceed 108”

  • Packaging provided
  • Next-day and second-day delivery guaranteed
  • Delivers even on Sundays and federal holidays
  • Signature delivery confirmation included

  • Most expensive option
  • Cannot use branded packaging

Special Considerations

As an extension of standard Priority Mail, it comes with many of the same requirements, and is also subject to dim charges when applicable.

Optimum Use Case

Express is best for time-sensitive deliveries, where the importance of speed outweighs cost. That said, the lighter the shipment and shorter the distance, the less expensive it will be.

Leverage the Power of Priority

USPS Priority Mail rates are comparable to other major carriers, but businesses are often surprised by people how competitive the included benefits are.

If you’re ready to leverage the power of USPS Priority Mail, let’s talk. Maximize your savings on shipping costs by putting our industry expertise to work for your brand.