First-Class Mail International today covers only letters, postcards, and flats. Packages moved to a separate service years ago. A lot of guides online still blur that line.
Here is what first-class mail international actually covers in 2026, what it costs, and where it stops working for you.
What first-class mail international covers today
First-Class Mail International (FCMI) is the USPS service for letters, postcards, and large envelopes. It reaches more than 180 countries.
Letters can weigh up to 3.5 ounces. Large envelopes, which USPS calls flats, can go up to 15.994 ounces.
That is the entire scope. FCMI does not carry packages, boxes, or anything with real thickness. A padded mailer stuffed with a small item is a different service, not this one.
Why packages moved to a different service
Years ago, FCMI was the catchall for cheap international mail. That included small goods stuffed into an envelope.
USPS split that off into First-Class Package International Service (FCPIS). That is a separate product built for lightweight parcels.
FCPIS now handles packages up to 4 pounds. It covers items valued at up to $400, to the same roughly 180 countries. The split means a seller mailing a small item overseas is not actually using first-class mail international anymore.
Many sellers still call that shipment first-class mail international out of habit. Technically it now runs through FCPIS. That service has its own rules, its own pricing, and its own customs form requirements.
Current first-class mail international rates
A standard letter or postcard up to 1 ounce costs $1.75 with a single Global Forever stamp. That price never changes, even after a future rate increase. It covers every eligible destination at the same flat rate.
Large envelopes over that weight are priced by weight and destination. Prices start around $3.30 for the lightest flats. Heavier or oversized pieces climb from there, and USPS publishes the exact tiers in Notice 123.
| Mailpiece | Weight limit | Starting price |
|---|---|---|
| Letter or postcard | Up to 3.5 oz (1 oz for the flat $1.75 rate) | $1.75 |
| Large envelope (flat) | Up to 15.994 oz | From about $3.30 |
| Package (FCPIS, a separate service) | Up to 4 lb (64 oz) | From $19.40 |
What you cannot put in a first-class mail international envelope
USPS rules are specific here. Letters and flats sent through FCMI can only contain documents and correspondence. No trading cards, no jewelry, no small trinkets, and no merchandise of any kind.
If the contents have commercial value, or are not paper, the piece does not qualify for FCMI rules. It needs to ship as a package instead. This is one of the most commonly missed details among small sellers trying to save on international shipping.
Customs forms for first-class mail international
Plain correspondence and nonnegotiable documents do not need a customs form at all. Cash, checks, or anything with cash value changes that. So does anything beyond paper.
If your envelope does need a form, USPS offers an online tool that fills one out for you to print. Once contents cross into package territory under FCPIS, a complete customs form is required every time.
For what happens to a package once it lands abroad, see our guide on how long customs clearance actually takes.
How long first-class mail international actually takes
USPS does not publish a numeric delivery window for FCMI. The official USPS page for the service simply says delivery varies by destination.
That is a genuinely honest answer. Transit depends on the destination country’s own postal system once the piece leaves the US.
In practice, sellers and small business forums report first-class mail international landing anywhere from one to four weeks for most countries. North America is often on the faster end of that range.
Some sellers report far longer waits. A handful describe six to eight week delays on postcards and light mail since late 2024, well outside any window USPS advertises.
There is no tracking on a standard FCMI letter or flat. There is also no delivery guarantee on any USPS international service except Priority Mail Express International.
If a piece truly needs a paper trail, Registered Mail service can help. It is available to most destinations for an added fee.
First-class mail international to Canada and other close destinations
Canada is the most common FCMI destination for US senders, and the same $1.75 Global Forever rate applies. For anything heavier than a letter, our full breakdown of sending a package to Canada with USPS covers the package side.
That guide also covers customs thresholds your recipient may run into.
If you are unsure whether your item still qualifies as a letter, weigh it first. Check what is actually inside before you buy postage. A post office clerk can also confirm which service applies at the counter.
Estimating what your recipient might owe
FCMI letters carrying only documents rarely trigger duties. Once an item ships as a package under FCPIS, or under a pricier service, your recipient may owe import duties or taxes.
That depends on the destination country and the declared value. Our international duty estimator gives a rough sense of what your recipient might owe before you ship.
First-class mail international versus the domestic version
Domestic First-Class Mail and first-class mail international share a name but little else. The domestic version covers letters, postcards, and small packages up to 13 ounces within the US, with a published 1 to 5 business day window.
The international version has a tighter weight ceiling on letters. It gives no numeric delivery promise, and it bars shipping goods entirely.
Confusing the two is common. It explains a lot of the wrong expectations people carry into an international mailing.
If postage math for a domestic piece has you stuck, our guide to current Forever stamp prices covers those rates in full. Our breakdown of what a USPS package actually costs covers the domestic package side.
The bottom line
First-class mail international is the cheapest way to send a letter, postcard, or document filled flat anywhere USPS reaches, and nothing more. Packages, no matter how small, belong to First-Class Package International Service instead.
That service carries its own weight limit, price, and customs rules.
Budget real time for delivery. USPS will not commit to a number, and real world reports often run longer than expected. For anything with actual value inside, upgrade to a tracked service and fill out the customs form honestly.
