A Forever stamp on a letter to London does not send it to London. It sends it back to you, with a sticker on the front, roughly a week later — which is a genuinely expensive way to learn that "Forever" and "Global Forever" are different products.
Here is the distinction, and the weight threshold that catches people even when they get the stamp right.
Global Forever is a separate service tier
A standard Forever stamp is worth the domestic First-Class one-ounce rate. International postage costs more than that, always.
Global Forever stamps are the international equivalent: round, marked "Global," and priced at the international letter rate. One covers a one-ounce letter to any country USPS serves.
You can use domestic Forever stamps on international mail, but only by making up the difference with additional postage. What you cannot do is put one on and hope. Automated processing cross-references destination against postage paid, and a domestic stamp on a foreign address is flagged as a rate violation almost immediately.
The one-ounce threshold
This is the second trap, and it defeats people who bought the right stamp.
A single Global Forever stamp covers an international letter up to one ounce. That allowance is thinner than it sounds. A folded contract plus a cover letter is usually fine; add a business card, a second insert or heavier stock and you can cross the line.
Over the threshold without the additional-ounce surcharge, the piece comes back. Weigh a fully assembled sample — everything that is going inside — before buying postage for the batch. Calibrate the scale periodically while you are at it.
Best deals on Forever stamps
Postcards do not get a discount abroad
Domestically, a postcard is cheaper than a letter. Internationally it is not — the same Global Forever stamp covers either, up to an ounce. Buying postcard-rate stamps for overseas cards is a common and pointless error.
When a letter is not the right product
For contracts and documents where the arrival date carries consequences, ordinary international letter mail is the wrong choice regardless of postage. Priority Mail International and Priority Mail Express International cost considerably more and come with tracking and faster, more predictable transit.
If a missed date would cost more than the shipping, pay for the shipping. That calculation is not close for anything contractual.
A quick compliance table
| Compliance trigger | Requirement | If you get it wrong |
|---|---|---|
| Postage type | Global Forever, or domestic plus difference | Returned as rate violation |
| Weight | Under 1 oz for a single Global stamp | Returned for insufficient postage |
| Deadline-critical mail | Priority Mail International or Express | No tracking, unpredictable transit |
The 40%-off Global stamp problem
Global stamps cost more at retail than domestic ones, which makes them a favored bait for counterfeit sellers advertising on social media.
Genuine stamps carry phosphor tagging that sorting equipment verifies on every piece, and untagged stock is pulled from the stream rather than delayed. On international mail that means a document that leaves your office and simply stops.
Legitimate secondary-market sourcing supports roughly 10–20% off. A "Global Stamps 40% Off" ad is not a supplier you found first.
Where to buy
The USPS official store, or a specialist such as Forever Stamp Center that carries both Global and domestic stock and issues a real invoice. Watch USPS service alerts for overseas hub bottlenecks, and the Postal Regulatory Commission plus the USPS Notice 123 charts for rates. For an urgent drop, the USPS location finder.
The short version
Global Forever for international letters. Weigh the assembled piece and stay under an ounce or add the surcharge. No postcard discount abroad. And for anything with a deadline, buy the tracked service instead.
More on buying Forever stamps
- 👉 The Tangible Horizon: A Manifesto on the Enduring Power of Physical Stamps
- 👉 Sourcing the Most Popular Semipostal Stamps for Charity Online Safely
- 👉 Why Accounting Departments Prefer Pre-stamped Envelopes vs Bulk Stamps
Currently working at USPS in Chicago, he has more than 15 years of experience in bulk mailing and logistics. His columns focus on Forever Stamp trends, helping businesses and individuals make cost‑effective mailing decisions.
