How Much Is Each Additional Ounce of Postage?
Navigate the nuances of postage rates beyond the initial ounce. Learn how to accurately determine and apply additional mail charges based on weight.
Understanding postage costs is important when mail exceeds the weight covered by a standard stamp. Calculating the required postage prevents delays and ensures efficient delivery. Accurately determining mailpiece weight and additional charges helps manage mailing expenses.
Current Cost of an Additional Ounce
The current cost for adding an ounce to a First-Class Mail letter is $0.29, effective July 13, 2025. This charge applies after the initial ounce, which costs $0.78 for a standard-sized, rectangular letter. A single Forever Stamp covers the postage for a one-ounce First-Class Mail letter, regardless of future rate increases. The maximum weight for a First-Class Mail letter is 3.5 ounces.
Applying Additional Ounce Charges by Mail Type
Additional ounce charges vary depending on the type of First-Class Mail. For standard letters, the initial ounce costs $0.78, and each subsequent ounce, up to the 3.5-ounce maximum, incurs an additional $0.29. This means a 2-ounce letter would cost $1.07, and a 3.5-ounce letter would cost $1.57. Letters exceeding the 3.5-ounce limit or specific dimensions are reclassified and charged as larger mailpieces.
Large envelopes, also known as flats, have different base rates and weight limits. These items start at $1.63 for the first ounce, with each additional ounce typically costing $0.29, though the exact additional ounce rate for flats can vary slightly by weight range. Large envelopes can weigh up to 13 ounces and must meet specific dimensions, generally not exceeding 12 inches high, 15 inches long, or 0.75 inches thick. If a large envelope exceeds these size or weight limits, or is rigid or non-rectangular, it may be classified and priced as a package.
Accurately Weighing Your Mail
Accurately weighing your mail is a necessary step before calculating postage. Underpaying postage can lead to mail being returned to the sender or delivered with postage due, causing delays. Utilizing a kitchen scale or a dedicated postal scale can provide the precise weight needed. Weigh the mailpiece after it has been fully prepared with all contents inside.
When determining postage, the United States Postal Service (USPS) rounds up to the next whole ounce. This means a letter weighing 1.1 ounces will be charged at the 2-ounce rate, and a letter weighing 2.9 ounces will be charged at the 3-ounce rate. Understanding this rounding convention helps prevent discrepancies and ensures adequate postage.
Official Sources for Postage Rates
Consulting official sources for postage rates is recommended due to periodic adjustments. The United States Postal Service (USPS) website is the primary resource for current rates and mailing guidelines. It provides detailed information on all mail classes, including First-Class Mail, and offers tools to calculate specific postage costs. Regularly checking the USPS website ensures access to up-to-date information.
For in-person assistance, visiting a local post office can also provide current rate information. Postal clerks can accurately weigh mailpieces and advise on the correct postage. These official channels are the definitive sources for verifying rates and ensuring compliance.