Knowing when to use First Class Mail or Priority Mail is rather simple. Generally speaking, anything under 16 oz should use First Class Mail and anything over 16 oz should ship with Priority Mail. There are a few exceptions, of course. And we’ll cover those exceptions later. But for domestic shipments—particularly clothing and apparel.

Why Is It Called First-Class Mail?

First Class Mail may sound like it’s the top-tier service, and to a certain extent, it is. But this is not in comparison to Priority Mail. First Class Mail is a class of mail used to ship letters, thick envelopes, padded envelopes, and lightweight packages. First Class Mail is considered the top tier of mailed materials in comparison to:

• Second Class Mail: periodicals, magazines, newspapers that are printed more than 4 times a year.
• Third Class Mail: Marketing mail, flyers, mailers, etc.
• Fourth Class Mail: Media Mail (CDs, vinyl records, DVDs, books, bound print media consisting of 8 or more pages.)
  

Shipping T Shirts

Shirts, especially t-shirts are a good candidate to ship with First Class Mail. They’re light-weight and durable. Try using a poly mailers to cut down additional costs.

Why Is It Called Priority Mail?

Priority Mail is the USPS’s class of mail that is their top priority to ship out. It delivers parcels at a quicker speed than First Class Mail and allows for far heavier parcels (up to 70 lbs). Internationally, it is advantageous since it typically cuts shipping time down significantly. Because of this, it is a little bit more expensive than First Class Mail.

Priority Mail is also closer to UPS and FedEx services. However, it is frequently more economical than both UPS or FedEx for packages weighing under about 10 lbs. This is generally because a USPS vehicle passes by addresses each day. Smaller parcels that can fit in a mailbox typically are economical. If the parcel’s size/weight requires the delivery driver to leave their vehicle and/or are too large to fit in their messenger bag, then the price can begin to rise quickly.

Shipping Shoes

Shoes are almost always going to ship using Priority Mail (Unless they weigh less than 16 oz). Check to see if Flat Rate options offer discounts over standard Priority Mail packaging.

Max Dimensions and Weight

USPS First Class Mail is typically used for smaller, lighter parcels—weighing under a pound—with items whose insured value is not very high. Items over a pound and/or items of higher value work better with Priority Mail.

	USPS First Class Mail	USPS Priority Mail
Max Dimensions	108” in combined length and girth.*	108” in combined length and girth*
Max Weight	15.99 oz°	70 lbs*

*Exceeding these maximum restrictions may result in a $100 charge applied to you by the USPS.
°4.4 lbs for First Class International 

Max Default Insurance Coverage

A major advantage of USPS Priority Mail is that it includes coverage in the event that a parcel becomes lost or damaged in transit. First Class Mail offers no default coverage, however, both Priority Mail and First Class Mail do allow additional coverage to be purchased through the USPS or through a third-party provider such as Shipsurance.

	First Class Mail	Priority Mail
Domestic Coverage	N/A	$100*
International Coverage	N/A	$200*

Shipping Watches and Other Jewelry

While a watch almost always weighs under 1 lb and can be shipped with First Class Mail, Priority Mail offers up to $100 of coverage in the event that the parcel is lost or damaged.

Price Comparison

First Class Mail is a more economical shipping option than Priority Mail. If you would like a breakdown of the shipping rates available to you, check out these rates available to any ShipStation user through their complimentary Stamps.com account.

Transit Time

Now that First Class Mail uses USPS zones when rating, it’s easier to compare transit times. Let’s take a look at the estimated delivery time it takes for different locations around the US and globally:

DOMESTIC

USPS Service	Zone 1	Zone 3	Zone 5	Zone8
Media Mail	2 days	3 days	6 days	6-13 days
First Class Mail	2 days	3 days	3 days	3-5 days
Priority Mail	1-2 day	2 days	2 days	3 days
Priority Mail Express	1-2 days	1-2 days	1-2 days	1-2 days

International

Service	Estimated Transit Time
First Class Mail International	No guaranteed time frame
Priority Mail International	6-10 days*
Priority Express International	3-5 days*

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Media Mail

Media Mail is the USPS’s more affordable, slower option for shipping CDs, vinyl records, DVDs, books, bound print media consisting of 8 or more pages. Unlike other USPS services, the USPS can inspect the package to make sure the contents are approved materials without first authorizing a search warrant.

Shipping Vinyl Records

Vinyl records most commonly ship with Media Mail. As do books, CDs, DVDs, and other physical media. If expedited delivery is important, consider upgrading to First Class Mail or Priority Mail (depending on the weight or insured value).