First-Class Mail & Postage | USPS

First-Class Mail & Postage | USPS First-Class Mail Mail in 1–5 Days First-Class Mail® service is an affordable and easy way to send envelopes and postcards. First-Class Mail Forever® stamps cost $0.82 (the current 1 oz price) and will never expire, even if the First-Class™ postage rate goes up. To send packages, see USPS Ground Advantage® service. Features & Pricing Mail delivered in 1–5 days Our best-priced service for items up to 13 oz Postmarking & Proof of Mailing: If you want to ensure that your mail receives a postmark on the day you mail it, ask a retail associate at a Post Office retail counter to hand-cancel it for free. To get an official record that you sent an item on a specific date, you can pay an extra service fee for a Certificate of Mailing. Proof of Delivery: First-Class Mail items are eligible for Delivery Confirmation™ services such as Certified Mail®. One price for up to 3.5 ounces with commercially priced letters and cards Prices based on shape and weight Standard Letter & Postcard Sizes Letters: Standard-sized, rectangular envelope stamps start at $0.82. Square, oversized, or unusually shaped envelope stamps start at $1.31. Postcards: Standard-sized, rectangular postcard stamps start at $0.65. Oversized postcards need letter stamps, which start at $0.82. Large Envelopes: Large envelopes (flats) start at $1.69. Weight, Size, & Shape Requirements Maximum weight for First-Class Mail letters is 3.5 oz; for large First-Class Mail envelopes, the maximum weight is 13 oz. All postcards and envelopes (or flats) must be rectangular, otherwise an additional charge may apply. Additional size restrictions apply depending on the type of mailpiece you're sending. Additional Charges for Irregular Mailpieces & Envelopes Nonmachinable Envelopes: Unusually shaped mail, like square or vertical envelopes, lumpy envelopes, rigid envelopes, and mail with clasps, string, or buttons, must be hand-canceled. They are charged a nonmachinable surcharge even if they weigh less than 1 oz. Large Mailpieces: Letters that exceed the First-Class standard envelope maximum length, height, or thickness are charged large envelope (flat) prices. Large Envelopes (flats) Treated as Small Packages: Large First-Class envelopes (flats) that exceed maximum dimensions or are rigid, non-rectangular, or not uniformly thick are charged package prices and shipped with USPS Ground Advantage. Mailing Restrictions & Prohibitions: There are specific regulations and standards for mailing restricted, prohibited, and hazardous materials, including cigarettes and smokeless tobacco. For Businesses: USPS understands what's most important to business customers: speed, affordability, security, and customer service. Data-Driven Shipping: First-Class Mail is targetable, trackable (with certain extra services), and measurable, offering a wide range of options for businesses. With address correction and forwarding services, your messages will reach a greater percentage of your target audience. Commercial Prices & Automation Discounts: Bulk Discounts. First-Class Mail commercial pricing is available for presorted letters and flats with a minimum quantity of 500 mailpieces. Automation discounts may also apply. One Price Up to 3.5 Ounces: Pay one price for up to 3.5 oz for First-Class Mail presort and automation compatible letters and cards. This is a cost-effective way for businesses to include promotional messages with bills, invoices, and statements. The one price for up to 3.5 oz rate is not a blended rate and does not apply First-Class Mail single-piece letters.