Priority Mail International

Worldwide flat rate shipping: flat by box, not by country

Priority Mail International Flat Rate is flat in one sense only: the price ignores what the box weighs, up to the ceiling printed on it. It does not ignore where the box is going. USPS prints its own footnote against those figures — “Prices are based on regional destination” — and its retail price list carries a separate flat rate column for each of eight destination groups. The 32.65 USD Flat Rate Envelope quoted everywhere online is the Canada price; the same envelope to a group 7 country is 62.35 USD. The full ladder is below, read from USPS's own pages and price files on 2026-08-30.

Read from usps.com2026-08-30Eight destination groups, priced
Flat rate box prepared for an international shipment
One box, one price

The size decides the number. The country does not, except when its own listing adds a rule the general page never mentions.

The full flat rate ladder, group by group

USPS assigns every destination a flat rate price group, and each group has its own column in the published retail price list. Same envelope, same 4 lb ceiling, eight different numbers. The group examples below were read from USPS's own country price group table on 2026-08-30.

Priority Mail International Flat Rate retail prices by destination price group, effective 6/15/2026, read from usps.com/business/prices/2026/s-pmi-retail.csv on 2026-08-30. Ceilings: 4 lb on the envelope and Small Box, 20 lb on the Medium and Large Boxes.
Price groupFlat Rate EnvelopeSmall BoxMedium BoxLarge Box
1 (Canada)32.65 USD33.75 USD61.80 USD75.15 USD
248.80 USD50.45 USD90.85 USD102.55 USD
3 (India)49.75 USD51.40 USD96.40 USD121.30 USD
4 (Ireland)54.55 USD56.35 USD93.15 USD110.60 USD
552.30 USD54.00 USD95.95 USD108.85 USD
653.00 USD54.75 USD112.70 USD139.55 USD
762.35 USD64.45 USD133.10 USD155.00 USD
8 (Iceland, Iran)50.55 USD52.20 USD102.55 USD132.05 USD

Priority Mail Express International runs its own single flat rate envelope on the same group structure: 62.70 USD to group 1, 79.80 USD to group 3, 89.20 USD to group 6 and 102.50 USD to group 7, capped at 4 lb, read from usps.com/business/prices/2026/s-pmei-retail.csv on 2026-08-30. Note that the ladder is not a distance ladder — group 8 undercuts groups 4 through 7 on every line — so the group table is the only way to know which number applies.

USPS states Priority Mail Express International's delivery window as 3 to 5 business days and Priority Mail International's as 6 to 10 business days to many major markets, on both the flat rate and weight-based sides of each service. Customs holds sit outside both figures and are not something either page's day range accounts for.

What the USPS sentence actually excludes

USPS's own Priority Mail International page carries this line: “Except for Priority Mail International Flat Rate pricing, Priority Mail International prices are based on weight and destination country.” It is easy to read that as flat rate escaping the destination too. It does not. The same page footnotes its flat rate figures with “Prices are based on regional destination”, and the retail price file prints a separate flat rate column per group. What flat rate drops is the weight half of that pair: the box costs the same at 8 oz as at its ceiling. The weight-based alternative starts at 43.55 USD and climbs on both axes at once.

The same split exists on the Express side. Priority Mail Express International Flat Rate runs 62.70 USD to group 1 and 102.50 USD to group 7, ignoring weight up to 4 lb either way, while the weight-based version of the same service starts at 64.25 USD and moves on weight and group together.

Where the ceiling actually comes from

The 4 lb and 20 lb figures above are the general ceilings USPS prints on its main international product pages. They are not the last word. The USPS International Mail Manual keeps a separate page of country-by-country maximum weights, and its own individual country listings are where prohibitions and restrictions for a specific destination actually live, above and beyond whatever the general product page says.

Country limits can sit below the generic figure

Weight-based Priority Mail International's generic ceiling is 70 lb, but Albania's own listing caps it at 44 lb, and Algeria's at 44 lb as well — both read from the USPS International Mail Manual on 2026-08-30. Neither figure comes close to the 4 lb and 20 lb flat rate ceilings, but the pattern is the same one that eventually does: the country's own page, not the general one, sets the true maximum.

A country can close a door flat rate never mentions

Afghanistan's listing states that First-Class Mail International and First-Class Package International Service shipments may not contain dutiable articles at all — a restriction that exists nowhere on the general USPS page for either service. Priority Mail International, flat rate included, stays open to Afghanistan; the point is that a country's listing can shut a door the product page never hints at.

Check the destination before you tape the box

Nothing about a flat rate price tells you whether the destination accepts the contents. USPS's own guidance is that prohibitions and restrictions specific to a country appear under that country's listing, not under the service description, so the flat rate ladder above answers price and ceiling and leaves mailability to a separate lookup.

The domestic envelope against the international ladder

The same Flat Rate Envelope sold for domestic Priority Mail is 12.90 USD at the Post Office, per usps.com on 2026-08-30, against 32.65 USD for the cheapest international group and 62.35 USD for the dearest. What decides whether flat rate beats a weight-based label on the domestic side is covered on its own page rather than repeated here: see flat rate against weight-based shipping for the live comparison, and flat rate box prices for every domestic size and price.

SMKlog's checkout prices and prints domestic parcel labels only. What USPS, FedEx and UPS actually sell for shipments leaving the country, and the forwarder pattern that routes an overseas order through a US address on an ordinary domestic label instead, is the full subject of USPS international shipping, priced and explained. Customs paperwork itself is covered in customs forms and HS codes.

Flat rate questions, international side

Is USPS international flat rate shipping the same price to every country?

No. Flat rate means the price ignores the weight, not the destination. USPS's own price file for 2026 carries a separate flat rate column for each of eight destination groups, and its product page footnotes the figures with “Prices are based on regional destination”. The Flat Rate Envelope runs 32.65 USD to group 1 and 62.35 USD to group 7 — the same envelope, the same 4 lb ceiling, nearly double the price.

What does a Priority Mail International Flat Rate Envelope cost?

Between 32.65 USD and 62.35 USD at the Post Office or online, depending on the destination's price group, read from USPS's 2026 retail price file on 2026-08-30. The 32.65 USD figure quoted on the product page is the group 1 price, which covers Canada. The 4 lb ceiling and the 12 1/2 x 9 1/2 inch envelope are the same in every group.

What are the weight limits on USPS worldwide flat rate?

4 lb for the Flat Rate Envelope and the Small Flat Rate Box, 20 lb for the Medium and Large Flat Rate Boxes. USPS's own Priority Mail International page states those figures directly, and an individual country's own listing can still add restrictions on top of them, so the general ceiling is not a promise that every destination allows it.

Is there a flat rate version of Express Mail International?

Yes. Priority Mail Express International Flat Rate is an envelope capped at 4 lb, priced 62.70 USD to group 1 and up to 102.50 USD to group 7, checked 2026-08-30. The weight-based version of the same service starts at 64.25 USD and moves on weight as well as group.

Does a country's own listing ever override the general flat rate rules?

It can add restrictions the general product page never mentions. Afghanistan's listing in the USPS International Mail Manual states First-Class Mail International and First-Class Package International Service shipments may not contain dutiable articles at all, something the general USPS pages for those services do not say. Priority Mail International stays open there. The country listing, not the general product page, is what actually governs a given destination.

Where these figures come from

USPS revises prices, ceilings and country listings without notice. Treat the figures above as what USPS published on the date shown, and check the individual country listing for the destination actually on the label.

Dmitrii Timin founder of SMKlog

Runs SMKlog and its live rate comparisons across USPS, UPS, and FedEx. The guides here are built from the same carrier data the calculator quotes from, with prices captured on the date shown on each page. Based in Berkeley Heights, New Jersey.