First-Class Mail International: How to Send a Letter
The short answer
Sending a letter overseas? One Global Forever stamp ($1.75) covers a standard letter weighing up to 1 ounce. Write the destination address with the country on the last line, add your postage, and drop it in a USPS collection box.
The Letter Pilot doesn't currently offer First-Class Mail International, so you'll need to send international letters directly through USPS. Luckily, it's pretty easy. We'll walk you through the steps below.
How to mail a letter internationally
- Put your letter in an envelope. Use a rectangular paper envelope that bends easily, then seal it.
- Write the addresses. Put your return address in the top left, ending with USA. Write the recipient's address in the center, with the country name in English on the last line. Add “AIRMAIL/PAR AVION” on the front.
- Add postage. One Global Forever stamp ($1.75) covers a standard letter weighing up to 1 ounce. Heavier letters and unusual envelopes cost more.
- Mail it. Drop it in a USPS collection box or take it to the Post Office.
I see a lot of guides and online videos about sending international mail through the Post Office, and they almost always leave this part out: add “AIRMAIL/PAR AVION” to the front of your postcard or envelope. USPS requires this on the address side for First-Class Mail International. Make sure you don't miss this step.
Start with what is inside
You can't send goods or gifts with First-Class Mail International. If you want to send items overseas, use a package service such as First-Class Package International. It has different requirements, including a customs form.
How much postage do you need?
Make sure you weigh your sealed envelope. We use a kitchen scale a lot of the time when we're mailing. One Global Forever stamp costs $1.75 and covers a standard international letter up to 1 ounce. For a letter over 1 ounce and up to 2 ounces, it's an extra $0.60 for Canada, $0.85 for Mexico, or $1.75 for other countries. If you're sending documents and need a large, flat envelope, you'll pay a little extra. International large envelopes start at $3.30 for up to 1 ounce.
Envelope size and weight
| Limit | Letters | Postcards | Large envelopes |
|---|---|---|---|
| Length | 5½ to 11½ | 5½ to 6 | Up to 15 |
| Height | 3½ to 6⅛ | 3½ to 4¼ | Up to 12 |
| Thickness | 0.007 to ¼ | 0.007 to 0.016 | Up to ¾ |
| Weight limit | 3.5 oz | Not specified | 15.994 oz |
| Postage from | $1.75 | $1.75 | $3.30 |
Letter and large-envelope starting prices cover up to 1 ounce. Letters over 3.5 ounces pay large-envelope prices. Large envelopes must exceed one letter-size limit and be rectangular, flexible, and evenly thick.
If your letter is bumpy or uneven, USPS may charge you extra. For an international letter, that's currently 49 cents.
Write the address for the destination country
Put your return address in the upper-left corner, ending with USA. Write the recipient's address in the center, following their country's address order. USPS asks for the address in English; if you include another language, add the English translation after each line. Put the destination country in English, in capital letters, on its own last line. Postage goes in the upper-right corner.
Illustrative Canadian address layout
Replace each bracketed line with the address supplied by the recipient. Other countries use different address orders.
Does an international letter need a customs form?
No, not for a normal First-Class Mail International letter. You'll need a customs form when sending an international package.
Where can you mail it?
An eligible ordinary stamped international letter can go in outgoing mail, a USPS collection box, or a Post Office lobby drop. Check the posted collection time if you want it collected that day.
If you're not sure how much postage you should pay, take it up to the counter. Postal employees are some of the nicest people on the planet in my experience!
How long does it take?
The sign at the Post Office lists 3 to 5 business days for Priority Mail Express International, 6 to 10 for Priority Mail International, and 7 to 21 for First-Class Package International. For a regular letter sent with a Global Forever stamp, delivery time depends on the destination.
Before you mail
- Double-check the recipient's address, with the country on the last line.
- Weigh and measure the filled envelope.
- Make sure you've added enough postage for its weight, size, and destination.
- Check USPS international service alerts for any disruptions to your destination.
USPS sources
Reviewed October 8, 2026. These are USPS retail postage rules; destination restrictions and prices can change.
- First-Class Mail International overview
- Notice 123: current retail prices
- IMM 241: dimensions, weight, and nonmachinable letters
- IMM 242: eligible contents and IMM 243: postage by weight and destination
- IMM 123: customs forms and document exceptions
- How to prepare an international letter
- IMM 245: mail deposit and acceptance
- Registered Mail International: records and limitations
More help with international mail
USPS guide
USPS International Package Tracking: Updates & Help
Check USPS international tracking options, find your destination country’s tracking page, understand missing updates, and see when to open a USPS inquiry.
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USPS guide
How to Address an Envelope
Put your return address in the upper-left corner, the recipient address in the center, and postage in the upper-right corner. Here is the straightforward USPS-friendly format.
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USPS guide
How Many Stamps Do I Need? USPS Stamp Calculator by Weight and Envelope Type
Use the USPS stamp calculator to figure out how many Forever or additional-ounce stamps to use by weight and envelope type. Need dollar postage rates instead? See 2026 USPS postage prices.
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USPS guide
How to Address Military Mail (APO, FPO, and DPO)
Use the correct APO, FPO, or DPO military address format. Learn where the name, unit, AA/AE/AP code, ZIP Code, postage, and customs form belong.
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