Fourth Class Mail is a mailing service by USPS that provides cost-effective options for sending a variety of parcels and printed materials. Generally, this service takes more time to reach the intended recipients. However, the total postage cost is dependent on the package's size, dimensions, measurements, weight, destination, and additional services.

We can divide Fourth Class Mail into four categories: Library Mail, Bound Printed Mail, Media Mail, Parcel Select, and Parcel Post. It is an ideal mailing service for businesses that want to save on postage costs and maximize profits. Considering a direct mail automation tool is also a good idea to streamline mailing operations and find further savings opportunities.

Although USPS abolished the designation in 2004 during a restructuring of its mail class system, the services that replaced it remain active and widely used by businesses today. This guide breaks down the history of Fourth Class Mail, the reasons behind its retirement, its modern equivalents, the various service types, and how tools like PostGrid can streamline your direct mail operations from start to finish.

Types of 4th Class Mail

Below are a few types of fourth-class mail that you can use to elevate your direct mail campaign:

• Library Mail: The Library Mail service allows organizations like educational institutions and museums to exchange items. Library Mail is available to some other organizations if they are approved by the Postal Service. It is only possible to send books, video lectures, academic theses, and certain other items through the US Postal Service. If Library Mail is sent by you, it is possible to add services such as delivery confirmation, return mail, and limited delivery. In addition to the return address, you must include the name of the organization or institution you are affiliated with.
• Bound Printed Mail: This service is known as Bound Printed Matter and can be used to mail for healthcare, real estate, or law firms for advertising, promotional materials, directories, and informational materials like catalogs or phone books. The USPS allows mailers to send bound printed matter by imprint only, meaning they must have bulk mail accounts with the Postal Service. Rates depend on weight, distance, and size. BPM can weigh up to 15 pounds.
• Media Mail: A Media Mail service allows customers to send books, ebooks, cassettes, videos, CDs, DVDs, and diskettes along with video recordings. As part of the Media Mail service, you can select additional options, like delivery confirmation and delivery pickup. Depending on the package's weight, distance, and shape, Media Mail can weigh up to 70 pounds.
• Parcel Select: A large number of parcels are delivered through the Parcel Select service primarily by large and medium-sized shippers. By sending their mail from closer to their final destination, mailers save money on postage. Using Parcel Select, mailers choose one of three levels of service. From the USPS, you can choose from a variety of parcel delivery options, including Services offered by Parcel Select including delivery or signature confirmation, collections on delivery, return receipts, and limited 4th class mail delivery time.
• Parcel Post: Postal parcels are the most affordable option for mailers who cannot send Library Mail, Media Mail, or Business Priority Mail. There is a 70-pound maximum weight limit and a 130-inch maximum length and width combined for all packages. Additional services can be added to parcel post shipments, like delivery or signature confirmation, insurance, and delivery pick-up.

Know Your Options: Why it is Important For Your Business?

It is common for your business to ship hundreds or even thousands of packages a month. Shipping costs can greatly impact your profit margins. Even a small difference of $1-$2 can have a big impact. Choosing four-day delivery can save you up to 30% on shipping costs compared to having packages delivered within two days at a premium.

Knowing USPS mail classes is important for this reason. Depending on the different mail classes, you can choose the appropriate speed and cost for each package to offer customers the right shipping options without reducing profits.

Now that you know what is 4th class mail, let us now take a step ahead to see how to choose the perfect options for your business.

When you talk about other types of class mail options than fourth class mail– Priority Mail, the most cost-effective delivery method, meets most eCommerce businesses' standard delivery requirements. You will benefit greatly from using USPS Priority Mail as your default shipping method due to its attractive flat-rate options and moderate delivery speed.

Shipping costs will vary depending on the weight of the package you are shipping, how quickly it must arrive, and how much you are willing to spend. If you ship different types of products and items, you may also be interested in using Priority Mail Express or Marketing Mail.

Many eCommerce businesses are choosing to offer overnight shipping and 2-day shipping options as consumers want their products delivered faster than ever before. The Priority Mail Express service is a wise choice if you want to offer faster delivery options. You should charge your customers accordingly. Please be aware that it will be much more expensive than Priority Mail.

Compared to Fourth Class Mail, Priority Mail is either a day or two slower, but it is also much less expensive. Using the USPS's default shipping option is a great way to send items by mail.

Marketing-related items are the only items covered by these services. You have come to the right place if you are shipping marketing collateral, as PostGrid can help you with everything related to your direct mail services. In order to send promotional materials, consider using 4th Class Mail if you are still using direct mail for your eCommerce business.

PostGrid helps companies automate, address verification, track, and integrate their 4th class mail or other campaigns with digital marketing channels. Whether companies are seasoned veterans of direct mail advertising or this is the first time they are delivering advertisements in this channel, our system makes it easy for them to reap the benefits of direct mail.

While Fourth Class Mail is a retired classification, the services that replaced it, Media Mail, Marketing Mail, First-Class Mail, and Certified Mail, remain active USPS mail classes that businesses use daily for physical communications.

PostGrid's Print & Mail API enables businesses to automate sending across active USPS mail classes without managing print vendors, envelope stuffing, or postal logistics in-house.

Organizations in healthcare, financial services, insurance, and compliance use PostGrid to trigger compliant, trackable mail directly from their existing systems, via API, CRM integrations, or the PostGrid dashboard.

If your organization sends invoices, compliance notices, policy documents, or marketing materials at any volume, PostGrid handles the production, addressing, and USPS submission automatically, so your team focuses on the communication, not the logistics

1. Is Fourth Class Mail Still Available From USPS?
No, Fourth Class Mail is a retired USPS classification. The USPS abolished the Fourth Class designation in 2004 when it restructured its mail class system. The services that previously operated under it, including Media Mail, Library Mail, Parcel Select, and Bound Printed Matter, continue as separate, independently named USPS services with their own rates and eligibility rules.

2. What Replaced Fourth Class Mail?
The USPS replaced Fourth Class Mail with several distinct mail classes: Media Mail (for books, CDs, DVDs, and educational media), Library Mail (for exchanges between educational institutions and libraries), Parcel Select (for high-volume ground parcel shipping), Bound Printed Matter (for catalogs, directories, and advertising materials), and USPS Ground Advantage (the current standard retail parcel service, which replaced Parcel Post). Each successor service has its own eligibility requirements and postage rates.

3. What Was Fourth Class Mail Used for?
Fourth Class Mail was the USPS classification for parcels, merchandise, books, and printed materials weighing one pound or more that did not qualify for First Class or Second Class (periodicals) treatment. It was a lower-cost, slower delivery option commonly used by businesses, libraries, and publishers to ship non-urgent items cost-effectively. The modern equivalents serve the same practical purposes under updated naming.

4. How Long Did Fourth Class Mail Take to Deliver?
Fourth Class Mail delivery times varied depending on the subcategory and destination, but packages typically took anywhere from 2 to 9 business days. Media Mail, which is the most widely used modern successor, currently delivers in 2–8 business days according to USPS estimates, consistent with the historic Fourth Class timeframes for ground-shipped parcels.

5. Can I Still Use Parcel Post?
Parcel Post was discontinued by USPS in 2013 and subsequently replaced by Standard Post and then USPS Ground Advantage, which launched in 2023. USPS Ground Advantage is now the standard retail ground parcel service for packages up to 70 lbs. If you were using Parcel Post, USPS Ground Advantage is its direct functional successor.

6. What is the Cheapest Way to Ship a Package With USPS today?
The cheapest USPS shipping option depends on the item type. For books, media, and educational materials, Media Mail remains the most affordable option, typically costing significantly less than Priority Mail for heavier items. For general packages, USPS Ground Advantage offers competitive ground rates. For high-volume shippers, Parcel Select provides additional cost savings by entering mail closer to its destination. Commercial rates (available through third-party tools and direct USPS accounts) reduce postage costs further compared to retail counter pricing.