| Forever Stamp Definition | A Forever Stamp is a non-denominated postage stamp used by the United States Postal Service (USPS) that can be used to mail a one-ounce letter regardless of future rate increases. |
| Current Value | Equivalent to the current price of a First-Class Mail single-piece one-ounce letter, which is $0.63 as of 2024. |
| Weight Limit for One Forever Stamp | One ounce (1 oz) or approximately 28.35 grams. |
| Additional Ounce | Costs $0.24 per ounce for each additional ounce over the initial one-ounce limit. |
| Dimensions | Maximum size: 11.5 inches by 6.125 inches; Minimum size: 5 inches by 3.5 inches; Maximum thickness: 0.25 inches. |
| Non-machinable Surcharge | An additional $0.40 if the letter is rigid, non-rectangular, or not uniformly thick. |
| Maximum Weight for Letters | Up to 3.5 ounces with additional postage. |
| International Use | Forever Stamps can be used internationally but require additional postage based on current international rates. |
| Restrictions | Cannot be used for packages; limited to letters and flats meeting size and weight requirements. |
| Example Uses | Sending standard letters, greeting cards, legal documents, and lightweight items such as photos. |
| Estimation for Multiple Ounces | 1 oz = 1 Forever Stamp; 2 oz = 1 Forever Stamp + $0.24; 3 oz = 1 Forever Stamp + $0.48; 3.5 oz = 1 Forever Stamp + $0.72. |