Do You Need Special Stamps for International Mail?

You do not need any special stamp to send mail internationally from the United States. What you need is enough postage to cover the international rate, and the cleanest way to get there is a single Global Forever stamp, which costs $1.70 and carries a one-ounce letter or postcard to any country in the world.¹ Ordinary domestic Forever stamps work too, as long as you use enough of them. Heavier items and packages are a different story and usually require customs paperwork on top of the postage.

The Global Forever Stamp

The Global Forever stamp is USPS’s purpose-built option for international letters and postcards. One stamp covers a one-ounce letter or postcard to any destination worldwide, regardless of distance.¹ Like the domestic Forever stamp, it holds its value permanently. If the international rate goes up next year, a stamp you bought today still works with nothing added.

You can buy Global Forever stamps at any post office, through usps.com, or at some authorized retailers. At $1.70 each, they take the arithmetic out of international postage for anything letter-weight.

Using Regular Domestic Stamps Instead

Regular domestic Forever stamps are perfectly valid for international mail. The catch is that they aren’t worth as much individually. A domestic Forever stamp is currently $0.78, so one stamp falls well short of the $1.70 needed for a one-ounce international letter.²

Two domestic stamps come out to $1.56, which leaves you $0.14 short. You would need to add a low-denomination stamp to close the gap. Three domestic stamps total $2.34, which clears the rate but overpays by $0.64. So the math works, but rarely cleanly. If you send international mail even occasionally, keeping a few Global Forever stamps around saves both money and fuss. If you only have domestic stamps and need to get something out today, three will do it.

When Stamps Aren’t Enough

Stamps handle standard letters and postcards. Once you move past that, postage depends on weight, size, and where the item is going, and you’ll want to have USPS calculate it rather than sticking on stamps and hoping.

First-Class Mail International

The most affordable tier. Letters and postcards up to one ounce start at $1.70. Large envelopes, called “flats,” start at $3.15 and can weigh up to 15.994 ounces.³ Prices for envelopes over one ounce vary by the destination country’s price group.¹ Delivery times are not guaranteed and can run from about one to four weeks.⁴

Priority and Priority Express International

For packages or anything time-sensitive, Priority Mail International aims for delivery to many major destinations in 6 to 10 business days, and Priority Mail Express International aims for 3 to 5.⁴ Both include tracking and some built-in insurance.⁵ Rates depend on weight, size, and destination. The USPS online postage calculator or a clerk at the counter will give you the exact number.

Customs Forms for Anything That Isn’t Just Paper

Most international packages and any items containing goods require a customs declaration describing the contents, value, and purpose of the shipment. There is one exception that matters for stamp senders: First-Class Mail International letters and large envelopes under 15.994 ounces containing only documents do not need a customs form.⁶ A birthday card, a personal letter, or business papers can go out with just the right postage.

Anything else needs a form. USPS now requires customs forms to be generated electronically, either through Click-N-Ship, the Customs Form Online tool on usps.com, or at a post office counter where a clerk enters the information for you.⁷ Because of that, packages requiring customs declarations can’t just go in a collection box; they need to be brought to the counter.

Duties Your Recipient May Owe

Postage covers the trip. It does not cover import duties or taxes that the destination country may charge on arrival, and the sender cannot prepay them. Customs authorities assess the duty based on the declared contents and value, and the recipient pays on delivery.⁸ Low-value thresholds that used to exempt small shipments from duty have been shrinking in many countries, and the United States suspended its own $800 de minimis exemption in early 2026.⁹ If you’re sending a gift, warn the recipient a package is on its way so a duty bill at the door doesn’t surprise them.

Addressing and Drop-Off

Put the recipient’s address in the center of the envelope with the destination country’s name in English on the last line. Your return address goes in the upper-left corner with “USA” on the last line.³ Write the rest of the address in the format the destination country uses; postal codes and street ordering vary. When in doubt, ask the recipient how they’d write their own address and copy that, adding the country in English at the bottom.

A properly stamped letter or postcard can go in any blue USPS collection box. Anything with a customs form needs to be handed to a clerk at the post office so it can be scanned into the system. First-Class Mail International doesn’t include tracking by default; if you want visibility on the item’s journey, Priority Mail International builds tracking into the price.¹⁰

1
United States Postal Service. First-Class Mail International
2
United States Postal Service. USPS Announces No Stamp Price Changes for January 2026
3
United States Postal Service. How to Send a Letter or Postcard: International
4
United States Postal Service. International Mail Services and Shipping Rates
5
United States Postal Service. International Insurance and Extra Services
6
United States Postal Service. Customs Forms
7
United States Postal Service. IMM Revision: Customs Declaration Forms Acceptance Policies
8
U.S. Customs and Border Protection. Duty – Recipients of Gifts Mailed From Abroad
9
The White House. Continuing the Suspension of Duty-Free De Minimis Treatment for All Countries
10
United States Postal Service. International Shipping and Mailing