Additional Ounce Stamp: What It Is and When It Is Used

The Additional Ounce Stamp is a pre-printed postage option used by the United States Postal Service to cover the cost of mailing Lettters that exceed the first ounce. This stamp streamlines payments by providing a fixed surcharge for every additional ounce, helping mailers ensure proper postage without calculating exact fractions. Its use is guided by standard letter weight rules and varies with domestic versus international destinations. Understanding when and how to apply this stamp helps ensure mail reaches its destination without delays or extra handling.

What Is An Additional Ounce Stamp

An Additional Ounce Stamp is a postage label that covers the surcharge for each ounce beyond the initial first ounce on a standard letter. It is designed for mail that weighs more than one ounce but remains within the size limits for letters. The stamp is typically affixed to the upper right corner of the envelope along with the base postage for the item. By using this stamp, senders avoid recalculating total postage for every ounce increment and ensure compliance with the USPS weight-based pricing structure.

When Is It Required

It is required whenever a standard letter exceeds the first-ounce limit but does not require a different mail class or format. Key scenarios include:

• Domestic letters weighing over 1 ounce up to the maximum for a letter’s size.
• Letters that surpass the weight of a single ounce but remain eligible for First-Class Mail Letter service.
• When a mail piece’s weight increases due to added text, inserts, or enclosures, pushing the total above one ounce.

For international mail, different pricing applies. International letters and cards have their own weight thresholds and surcharge structures, so the corresponding stamp or metered option is used to cover the added ounces beyond the initial international rate. Always verify current rates at USPS.org before mailing.

How To Use And Apply

To use an Additional Ounce Stamp correctly, follow these steps:

• Weigh the mail piece to determine the total ounces. If it weighs more than one ounce, plan for the additional ounce surcharge(s).
• Affix the standard first-ounce postage for the destination along with the Additional Ounce Stamp for each extra ounce as required.
• Place stamps or metered labels in the upper-right corner of the envelope, ensuring they are clearly legible and not overlapping any other postage marks.
• Do not mix print-and-apply labels with stamps in a way that obscures any value or barcode that a postal worker must read.

Common mistakes include underestimating weight, forgetting to add the surcharge for each extra ounce, or placing stamps on the wrong side of the envelope. For large or irregularly sized pieces, consider using a postage calculator or visiting a local post office to confirm exact requirements.

Alternatives And Tips

Several options can simplify postage for heavier letters:

• Use a Flat Rate Envelope or Large Envelope if the size and weight fit and you anticipate frequent heavier mailings.
• Consider purchasing a Forever Stamp for up to one-ounce letters; for heavier mail, add the appropriate Additional Ounce Stamp.
• Explore online postage options that automatically adjust the total postage based on weight and destination, reducing manual calculations.
• Keep a small supply of Additional Ounce Stamps or a digital equivalent to avoid delays at the post office during busy mailing periods.

When preparing mail, always confirm current rates. USPS periodically updates weight thresholds and surcharges, and rate changes can affect the number of Additional Ounce Stamps needed. For the most reliable guidance, refer to USPS pricing schedules and official customer resources.

Example Rate Scenario

The following example illustrates how the Additional Ounce Stamp works in practice for a standard domestic letter with additional weight:

Note: The table reflects typical domestic First-Class Mail pricing for example purposes. Actual rates vary by year and destination; verify current figures on USPS.gov before mailing.