With its legacy of affordability and reliability, USPS Priority Mail has become the go-to shipping solution for many e-commerce businesses. And with multiple options available at different service levels and price points, it’s easy to find a delivery option that suits your needs and budget.

The Four USPS Priority Mail Service Levels

When it comes to USPS Priority Mail, you have four different service levels to choose from—all of which can be scheduled for pickup from your home or business, via the Shippo web app.

USPS Priority Mail Cubic

The best discounts—up to 90% off Retail rates! For packages weighing 1-20 pounds and about the size of a shoebox. Delivery in 1-3 business days, and tracking and insurance included.

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USPS Priority Mail Flat Rate

The easiest option, but not always the cheapest. If it fits, you can ship anything up to 70 lbs. for one flat rate. Delivery in 1-3 business days, and tracking and insurance included.

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USPS Priority Mail Regional Rate

Rates are set based on the distance traveled. Good for packages up to 15 or 20 lbs. Delivery in 1-3 business days, and tracking and insurance included.

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USPS Priority Mail (Weight-based)

Good choice for items up to 70 lbs., especially if they don't qualify for the other options. Delivery in 1-3 business days, and tracking and insurance included.

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Which Is the Best Option for My Business?

Each of the USPS Priority Mail service levels exist to support different shipping needs. Learn more about the "sweet spots" of each to ensure you're making the right choice.

USPS Priority Mail Cubic

The USPS Priority Mail Cubic service level offers rates up to 90 percent off Retail. The price is based on the size (length x width x height) of each package. Through this option, you can ship a package up to a half cubic foot in volume, which roughly equates to just smaller than 12 x 12 x 6 inches (or another combination that totals the same volume, with a maximum size of 18 inches for any dimension). Packages shipped through Priority Mail Cubic can weigh up to 20 pounds.

Often, USPS Priority Mail Cubic is your best, most affordable service level when shipping small packages that weigh at least a pound and no more than 20 pounds. Packages are generally delivered within 1-3 business days, tracking service is complimentary, and $100 of insurance is included at no additional charge.

Learn more about USPS Priority Mail Cubic pricing.

USPS Priority Mail Flat Rate

The USPS Priority Mail Flat Rate option is the only USPS Priority Mail service that isn’t priced based on weight and zone. Instead, you pay a flat rate for your shipment, with Shippo prices starting at $7.40.

Because the amount you pay isn’t impacted by weight or distance traveled, USPS Priority Mail Flat Rate tends to be the best choice when shipping small, heavy packages that are traveling long distances.

The following are a few popular Flat Rate products:

• Flat Rate Envelope: Dimensions are 12 ½ inches x 9 ½ inches, and the rate is $7.60 with Shippo.
• Small Flat Rate Box: Dimensions are 8 11/16 inches x 5 7/16 inches by 1 ¾ inches. Rate is $8.10 with Shippo.
• Large Flat Rate Box: Dimensions are 12 ¼ inches x 12 ¼ inches x 6 inches, and the rate is $18.95 with Shippo.

USPS Priority Mail Flat Rate packages are generally delivered within 1-3 business days within the U.S. territories, come with free tracking, and include $100 in insurance. Keep in mind you must use the USPS Priority Mail Flat Rate envelopes or boxes in order to ship with this service level.

Learn more about USPS Priority Mail Flat Rate.

USPS Priority Mail Regional Rate

USPS Priority Mail Regional Rate has been discontinued as of January 2023. The Postal Service is efforting to simplify Priority Mail pricing and will accept regional rate boxes if you have them. They will not create any more. Priority Mail Cubic will likely be your best alternative.

USPS Priority Mail (Weight-based Rates)

Need to ship a package up to 70 pounds that doesn’t qualify for the other options above? Check out the USPS Priority Mail (weight-based) service. This option allows shippers to send domestic packages affordably, without compromising the speedy delivery times e-commerce sellers rely on.

Technically speaking, this service level is simply called USPS Priority Mail. We add the “weight-based” descriptor to help our customers differentiate between regular ‘ol Priority Mail (a.k.a. weight-based) and its child service levels mentioned above: Priority Mail Cubic, Priority Mail Flat Rate, and Priority Mail Regional Rate.

Through this service, sellers can ship packages weighing up to 70 pounds with delivery in 1-3 business days. In terms of maximum package size, the overall girth can be up to 108 inches (the length of the longest side, plus the distance around its thickest part).

Those who ship via USPS Priority Mail service can also take advantage of free package pickups from their home or office (which you can schedule for free in the Shippo web app), as well as USPS tracking and up to $100 insurance on most packages with Shippo.

We like to think of Priority Mail (weight-based rates) as a catch-all. If your package doesn’t qualify for Cubic or doesn’t fit in a Flat or Regional Rate box, then you’ll use Priority Mail (weight-based). It also tends to be the best option for really lightweight packages (think 1-6 pounds).

How Much Does It Cost to Ship Priority Mail (Weight-based Rates)?

USPS Priority Mail (weight-based) service rates start at $6.64 through Shippo. The exact amount you pay mainly depends on a few factors — how much the package weighs, how far you’re shipping it, and where you buy your postage.

Check out Shippo's 2024 USPS postage rates:

Worth noting that the Postal Service changes its rates each year, including for USPS Priority Mail. These changes occur every January. In recent years, these rates have also been subject to peak season increases. The Postal Service has enacted those temporary increases to account for the surge in parcel volume during the months of October through December.

It's also worth noting that these rates extend out to packages weighing up to 70 pounds. The heavier your package the more you can expect the shipping cost will be.

How Fast is the Postal Service's Priority Mail?

The USPS promotes all of its Priority Mail services as including delivery within 1-3 business days.

Is Priority Mail Guaranteed to Arrive in 3 days?

According to the USPS, “In most cases, the expected delivery date printed on your receipt or provided at checkout will reflect a delivery time of 1, 2, or 3 business days and is based on origin, destination, and drop-off time. The expected delivery data does not come with a money-back guarantee.”

If needed, the Priority Mail Express service does offer delivery day guarantees, though it comes with a higher cost for the privilege.

Is Priority Mail Faster Than Regular Mail?

USPS Priority Mail does a good job of balancing cost and speed. With Priority Mail, you can affordably ship your package anywhere in the contiguous U.S. within 1-3 business days. As an alternative, USPS Parcel Select service takes an estimated 2-8 business days to ship packages weighing up to 70 pounds.

What are the Benefits of USPS Priority Mail?

USPS Priority Mail service offers a number of different benefits beyond those listed above:

• It’s Flexible: With several pricing options available, it’s easy to find the exact pricing for your shipping needs.
• It’s Affordable: Priority Mail rates are some of the USPS’s most cost-effective options, making them perfect for e-commerce sellers who need to keep a close watch on expenses and margins.  
• It’s Reliable: USPS is one of the most trusted U.S. couriers, while the tracking and insurance included offers some peace of mind.  

Who Delivers Priority Mail?

Most USPS Priority Mail is delivered by mail route carriers employed by the USPS. In some cases, however, the USPS uses contracts delivery suppliers to supplement the work of its employees.

Will Priority Mail be Left at the Door?

One big benefit to shipping via USPS? The Postal Service is the only carrier with authorization to open your mailbox. That means that while the other carriers have to leave parcels on your porch or lobby, the USPS can tuck items in your mailbox for safe keeping. Since it’s a federal crime to tamper with items in someone’s mail, this adds greater protection for your packages.

If your parcels don’t fit in your mailbox, however, USPS Priority Mail shipments may be left at your recipients’ doors, but a number of factors play into your packages’ ultimate destinations:

• If you’ve added Signature Confirmation, Signature Confirmation Restricted Delivery, or other related extra services to your shipment, they may not be left at the door if your recipient is not available.
• If your recipient has a usps.com account and has set up specific Delivery Instructions for your package, it will generally be delivered according to their instructions.
• In some cases — including areas where a high number of thefts have been reported, areas where aggressive animals are present, or homes with mailboxes that are too small to safely receive packages — carriers may leave a notice that the package must be picked up at the local Post Office branch.

How Do I Send Priority Mail?

While you can purchase USPS Priority Mail postage at any Post Office branch, an easier--and significantly cheaper--way is to use Shippo.

On average, Shippo’s rates for USPS Priority Mail are 20.1 percent lower than Retail rates, which are what you’d pay at the Post Office counter. However, they can go much lower than that, with discounts as low as 90 percent in some cases.

Offering discounts like these is possible because Shippo partners with more than 50 global carriers, including USPS, and has more than 70,000 e-commerce merchant customers. This allows us to pass on volume discounts to our users that they may not be able to negotiate with the carriers on their own.

Here’s how Shippo’s discounts look in practice.

Especially if you’re shipping packages at scale, Shippo’s discounts can translate into massive savings that make it possible to accelerate the growth of your e-commerce business.

Can You Use Your Own Box For USPS Priority Mail?

Yes, you can use your own box to ship via USPS Priority Mail. You can also use any USPS-branded box that is specifically labeled with USPS Priority Mail on the outside.

Shippo’s USPS Shipping Calculator

Want to see exactly how much you’ll pay based on current weight-based rates? Try Shippo’s USPS Shipping Calculator to instantly see your discounted rates.

Get started by entering:

• Where you’re shipping your package from and where it’s going
• What type of package it is (custom package, envelope, etc.)
• Your specific package dimensions (length, width, and height)
• Your package’s weight

Other Perks of Using Shippo

Besides saving money, Shippo lets you quickly and conveniently print out customized labels for your packages, including return labels. You can also schedule a pickup with USPS to save time, allowing you to focus on running your business — not waiting in line at the Post Office.

Shippo also offers robust package tracking so you can keep your customers in the loop and give them an ETA for your shipment. Finally, use our comprehensive reporting tools for a bird’s eye view of your shipping spend and overall efficiency to make continuous improvements.

Easy Access with Shippo

Overall, USPS Priority Mail service is an ideal option for sending domestic packages weighing up to 70 pounds. Get access to the best rates and save up to 90 percent off Retail rates by signing up with Shippo.