What is Priority Mail and How Does It Compare To First Class?

It's an affordable way to ship select letters and packages in a timely manner.
Person delivering package

U.S. Postal Service Priority Mail is a fast and affordable way to ship your letters and packages within the United States, with a flat rate option. Fun fact: Priority Mail was introduced by the postal service in 1968. The iconic flat rate envelope we all recognize today made its debut in February 1991, offering flat rate pricing for packages regardless of weight or destination. This really simplified the shipping process for the majority of customers.

USPS First Class mail is affordable and perfect for lightweight packages, regular envelope mail, and postcards. Postage stamps fall into this category as well, First-Class Forever stamps never expire and hold their value even if the First Class postage rate increases. The first postage stamps made their debut in 1847, but the first Forever stamp went on sale in April 2007, and has sold more than 6 billion thus far. There are several things to keep in mind when comparing priority and first-class mail which will be expanded on throughout the article.

Things to Know About Priority Mail

What Is Priority Mail?

This is the USPS service that gets top priority to be sent out. The service will also allow you to schedule package pickup if you don't have time to drop off your packages. The pickup service is free, which is a great convenience for customers.

What Is Priority Mail Express?

Priority Mail Express is similar to regular Priority Mail, but packages shipped via the Express service are given even higher priority on being shipped out. This is USPS' fastest delivery service, with either two-day or next-day arrival by 6 pm. They also offer a refund if your package is later than the quoted time. Customers can also pay an additional fee for Sunday or holiday delivery. If Sunday or holiday delivery is necessary, Priority Mail Express is the only service option.

How Much Does USPS Priority Mail Cost?

The cost for Priority Mail packages depends on their size, but because USPS provides the packaging and boxes, it is easier to determine the prices. They also have flat rate pricing, and if your items fit in the box, no matter how much it weighs, it will be the listed price. You can stuff the box full but there is a limit of 70 pounds. Anything heavier will have to be shipped by alternate carriers like UPS or FedEx.

Does USPS Priority Mail Include Tracking?

All Priority Mail includes tracking. Once you purchase a label, you will receive the tracking number. You'll be able to see the progress of your package while in transit, and see when it's out for delivery. Some tracking also includes a live map to see the point to point movement.

What Are the Advantages of USPS Priority Mail?

This shipping method is very popular amongst customers, and is well known for reliable service within the United States at an affordable price. It also offers:

  • Tracking: package tracking is automatically included with all Priority Mail packages for no additional charge
  • Convenience: free package pickup can be scheduled or easily dropped off at any post office location
  • Package returns and forwarding: all packages shipped with Priority Mail can be returned to sender or forwarded to a different address without any additional costs

Is Priority Mail Guaranteed To Arrive Within Three Days?

The only service that provides a guarantee with a refund is Priority Mail Express. With Express, if your item doesn't arrive at its destination within two days, you're eligible for a full refund. Standard Priority Mail service does not have a money-back guarantee.

Does USPS Priority Mail Deliver on Sundays?

Standard service does not deliver on Sundays, but they do include Saturday delivery for no additional charge. If you require Sunday delivery, the service you should choose is Priority Mail Express. For shipping heavier items that need Sunday delivery, UPS and FedEx have options available.

Does Priority Mail Ship Faster Than Flat Rate Shipping?

The listed delivery times for both Flat Rate and Priority Mail are the same, estimated to arrive at their destination within 2-3 business days. Priority Mail Express is the only service with guaranteed delivery within 1-2 days depending on distance. States that are not a part of the continental U.S. like Hawaii and Alaska will take extra time.

Can Priority Mail Be Insured?

All Priority Mail has insurance included without any additional fees. Coverage is either $50 or $100, and covers loss, damage, and missing merchandise. Additional coverage can be purchased if needed for extra fees.

Frequently Used Priority Mail Flat Rate Box Dimensions

There are many different flat rate and Priority Mail boxes, but the most commonly used ones and their dimensions are shown below:

Priority Mail Box Outside Dimensions Inside Dimensions
Small Flat-Rate Box 8 11/16" x 5 7/16" x 1 3/4" 8 5/8" x 5 3/8" x 1 5/8"
Medium Flat-Rate Box (opens from the top) 11 1/4" x 8 3/4" x 6" 11" x 8 1/2" x 5 1/2"
Medium Flat-Rate Box (opens from the side) 14" x 12" x 3 1/2" 13 5/8" x 11 7/8" x 3 3/8"
Large Flat-Rate Box 12 1/4" x 12 1/4" x 6" 12" x 12" x 5 1/2"

Can You Use Your Own Box for Priority Mail Shipping?

As long as you aren't shipping with Flat Rate shipping, you're able to use your own box, bag, or even recycled packaging. If you do choose to use a recycled box or bag, be sure to remove any previous shipping labels and cross off or cover up any bar codes. Flat Rate shipping requires the USPS box since the pricing is based on the package itself. These boxes can be ordered online to be delivered to your home, or you can pick them up free from your nearest post office. Something to note: it is illegal to use the free USPS packaging boxes for anything else besides USPS shipping.

Things to Know About First-Class Mail

What Are the Different First-Class Services?

First-Class service is broken up into three different categories.

  • First-Class Mail: This is for letters, either postcards or standard sized envelopes that weigh up to 3.5 ounces
  • First-Class Mail Flats and Large Envelopes: This service is for larger and heavier flat documents like legal papers, magazines and booklets, but with a weight limit of up to 13 ounces only
  • First-Class Mail Parcels: Your small packages and boxes that weigh less than 13 ounces can ship via this method, with tracking and delivery confirmation included

Package Size Requirements for First-Class Mail

Type Weight Limit Size Minimum Size Maximum Thickness
Envelopes Up to 3.5 ounces 3½" x 5" 6⅛" x 11½" 0.009" to ¼"
Postcards Up to 3.5 ounces 3½" x 5" 4¼" x 6" 0.007" to 0.016"
Large envelopes or 'flats' Up to 13 ounces 6⅛" x 11½" 12" x 15" ¼" to ¾"

How Is First-Class Mail Priced?

All mail in this category is priced on a per-ounce basis, roughly based on the price of First-Class Mail stamps. Additional fees may be applicable if an item is not machinable, and has to be hand sorted. Volume discounts on commercial rates are also eligible for retailers using this shipping service.

Priority Mail vs. First-Class Mail

What Are the Differences Between Priority Mail and First-Class?

  • Priority Mail can be used for larger and heavier packages, up to 70 pounds
  • First-Class will usually be cheaper when shipping lightweight items
  • Priority Mail will be typically faster than First-Class, with an estimated 1-3 delivery days versus 1-5 days
  • USPS tracking and insurance is included with all Priority Mail services. Not all First-Class services provide these

How To Choose Between Priority Mail and First-Class

When deciding between these two USPS services, there are a few things to consider to determine which one would be right for your shipping needs.

  • The distance your package needs to travel
  • The size and weight of your items or box
  • The speed in which you want your items to be delivered

Before you decide, you should also consider what feature you prioritize for your shipment. For example, it's the holiday season and you've procrastinated and are late to mailing Christmas gifts to your family. This situation might have you choosing speed over price, to ensure your gifts get there in time. Another situation may have you prioritizing cost savings over speed, if you're sending an item that isn't time sensitive.

The general takeaway to remember is that Priority Mail is great for faster shipping speeds and heavier items (up to 70 pounds), and First-Class Mail is usually a cost-effective yet reliable way to send regular mail and small packages up to 13 ounces.

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DealNews may be compensated by companies mentioned in this article. Please note that, although prices sometimes fluctuate or expire unexpectedly, all products and deals mentioned in this feature were available at the lowest total price we could find at the time of publication (unless otherwise specified).


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1 comment
No mention of USPS Ground Advantage. It used to be that under 1 lb you could ship First Class. Now that has changed in the recent months with the introduction of USPS Ground Advantage. I sell on eBay and ship nearly everything Ground Advantage now. They also let you go over a pound in weight that First Class never allowed. They also really raised the rates on Flat Rate boxes, so high that you can usually ship cheaper using Fed Ex or UPS. I really surprised that you didn't even mention the new Ground Advantage program. Keep up the good work. Larry S.