One ordinary domestic Forever stamp covers an eligible stamped First-Class Mail letter up to 1 ounce. It does not cover a flat, package, international letter or a square/rigid letter merely because that item also weighs one ounce.
A practical paper-count estimate
One ordinary Forever stamp covers a qualifying domestic letter only through 1 ounce. A typical #10 envelope plus three to five sheets of ordinary 20-pound printer paper often remains near that limit, but paper stock, inserts, cards and envelope weight vary. Treat this only as a planning estimate: assemble, seal and weigh one finished piece. If it exceeds 1 ounce, use the current additional-ounce schedule.
| Completed stamped letter | Postage effective July 12, 2026 |
|---|---|
| Up to 1 oz | $0.82 |
| Over 1 oz up to 2 oz | $1.11 |
| Over 2 oz up to 3 oz | $1.40 |
| Over 3 oz up to 3.5 oz | $1.69 |
Letter limits behind the answer
- Maximum letter weight: 3.5 ounces
- Maximum letter dimensions: 11.5 inches long, 6.125 inches high and 0.25 inch thick
- Machinability also depends on aspect ratio, flexibility, surface and attachments
- A fraction over an ounce moves to the next weight step
Do not count paper sheets
Paper type, envelope, inserts, tape and moisture all affect weight. Assemble and seal one complete sample, then use a postal scale. A page-count estimate cannot establish postage.
Examples
| Finished item | Starting decision |
|---|---|
| Ordinary rectangular letter, 0.9 oz | One domestic Forever stamp |
| Ordinary rectangular letter, 1.4 oz | $1.11 total postage |
| Square invitation, 0.9 oz | $0.82 plus $0.49 nonmachinable surcharge |
| 9×12 envelope, 0.9 oz | Evaluate as a large envelope/flat; do not use letter price |
| International letter, 0.9 oz | Use international rules and destination conditions |