Letter Stamps: Post Office and Stores

Letter stamps sell at post offices, many stores and online. Forever stamps cover a standard one ounce letter.

Updated Oct 26, 2026. Edited by: Ilyass Ben Hakim.

Where to buy

Post offices sell every stamp type. Grocery stores, pharmacies and some ATMs sell books of 20. Self service kiosks at many post offices sell stamps after hours.

Professional insight

Mailroom staff match postage to weight, size and destination. One stamp only covers a standard letter.

Square or rigid envelopes need extra nonmachinable postage.
International letters need a Global Forever stamp.
Stamps sold far below face value are often counterfeit.
Weigh thick cards before mailing.

Check the label

Says Forever, Global Forever, Postcard or a printed cent value.
Issued by USPS, not a novelty sticker.
Stamp count on the book or coil, such as 20.
Self adhesive backing intact and unused.
No cancellation marks or ink on the stamp.
Sold at or near face value by a known seller.

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Types

Common US letter stamps
Stamp	Covers	Notes
Forever	First Class letter up to 1 oz	Always worth the current rate
Additional ounce	Each extra ounce on a letter	Add to a Forever stamp
Nonmachinable surcharge	Square, rigid or lumpy letters	Added on top of postage
Postcard	Standard size postcards	Lower rate than a letter
Global Forever	1 oz letter to any country	Round stamp design

Ways to save

Buy Forever stamps before an announced rate increase.
Forever stamps keep their value after prices rise.
Use postcards for short notes.
Keep mail flat and light to avoid surcharges.

Common questions

Do Forever stamps expire?: No. They stay valid for First Class letters at the current rate.
How many stamps does a heavy letter need?: Weigh it. Add postage for each ounce over one.
Can I print postage at home?: Yes, through USPS Click N Ship or approved postage services.