The Postal Service divides mail into different services, called "classes." Each class of mail has different features, service levels, postage rates, and presort requirements.

For most of your mailings, the content of the material and postage rate will determine the class of mail you select. To learn more about each class of mail—including what can be mailed, the minimum and maximum weights and sizes, and the number of pieces needed for discounted postage rates—just click on the name of the class of mail. Not sure which class of mail is right for your mailing? Look at the matrix below to determine what class of mail best matches your priorities.

If you are unsure about what class your mailpiece will—or should—be, contact your local business mail entry unit for advice.

Ratefold - Notice 123 (PDF)

Domestic Mail Manual - Rates and Fees (HTML)

Business Rate Calculator – Compute rates for all discount mail.

Download Adobe Acrobat Reader

Overnight/Express Mail: Anything mailable, letters, merchandise.

First-Class Mail (including Priority Mail): Anything mailable, bills, invoices, personal correspondence, merchandise.

Periodicals: Newsletters, magazines.

Standard Mail: Advertisements, circulars, newsletters, magazines, small parcels, merchandise. Must weigh less than 16 ounces.

Package Services: Merchandise, catalogs, printed material, computer media.