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.