Last reviewed: August 25, 2026. Postal prices can change; verify unusual pieces with USPS before mailing.
For a standard domestic letter weighing 1 ounce or less, one regular Forever stamp is enough in 2026. A 2-ounce machinable letter costs $1.11 and a 3-ounce letter costs $1.40. Since each Forever stamp is worth $0.82, two stamps cover either weight, although adding exact additional-ounce postage wastes less.
Domestic letter examples
| Machinable letter | 2026 price | Whole Forever stamps |
|---|---|---|
| Up to 1 oz | $0.82 | 1 |
| Over 1 oz through 2 oz | $1.11 | 2 |
| Over 2 oz through 3 oz | $1.40 | 2 |
| Over 3 oz through 3.5 oz | $1.69 | 3 |
The whole-stamp column rounds up. You may combine a Forever stamp with other valid denominations to pay closer to the exact price.
Identify the mailpiece before counting stamps
Weight alone is not enough. A letter must stay within letter dimensions and meet shape and flexibility standards. A square, rigid, or uneven envelope can require a surcharge or parcel price. A larger flexible document envelope may be a flat.
- Large envelope and 9×12 flat postage
- Square, rigid, and nonmachinable envelopes
- Packages paid with Forever stamps
A reliable five-step calculation
- Seal the piece with everything inside.
- Weigh it accurately.
- Measure its length, height, and thickness.
- Choose the correct mail class and check current USPS prices.
- Divide the required postage by $0.82 and round up only if using regular Forever stamps alone.
Our postage calculator can do the final stamp-value arithmetic. For mailing to Canada, use the separate Canada stamp table; for other countries, use the Global Forever guide.
Common mistakes
Estimating from page count
Paper stock, envelope material, cards, clips, and inserts change the weight. Weigh the finished piece.
Using an old purchase price
A Forever stamp’s current postage value matters, not what you paid for it. Check the current Forever stamp price.
Treating every envelope as a letter
Large, thick, rigid, or lumpy pieces can enter a different price category. Extra stamps do not correct an incorrect mail classification.
Frequently asked questions
Can I put two Forever stamps on a 2-ounce letter?
Yes. They provide $1.64, which covers the 2026 $1.11 price, but exact additional-ounce postage costs less.
Will extra stamps make mail arrive faster?
No. Extra postage does not upgrade the service unless you actually select and pay for an eligible faster service.
Can old Forever stamps be combined?
Yes, if they are genuine and unused. Each regular Forever stamp has the current domestic one-ounce letter value.