All Things Shipping
Dec 6, 2023

Quick Guide To USPS International Shipping: Services, Rules, Costs

USPS isn’t necessarily the first service that comes to mind for e-commerce business owners when shipping internationally. But it can be one of the most reliable and affordable ways to ship across country lines, offering multiple service level options to suit the needs of most companies.

We’ll discuss everything you need to know about international shipping with USPS, the various service levels that are available, and how you can save when it comes to international shipping.

USPS International Shipping Time Options

USPS has a robust international shipping program, with many popular service levels that accommodate a variety of needs and budgets. While the list below is not a comprehensive list of USPS international services, the following services are among the most common programs retailers are likely to use.

  • Priority Mail Express International: 3-5 days’ ship time
  • Priority Mail International: 6-10 days’ ship time
  • Priority Mail International Flat-Rate: Ship time varies
  • First-Class Mail International: Ship time varies
  • First-Class Package International Service: Ship time varies

Service Level Pricing and Details 

For more on each option’s pricing, limitations, insurance, and extra services, check out the following service level breakdown:

Priority Mail Express International

Service Profile

Priority Mail Express International is a popular USPS international shipping service, thanks to its balance of speed, price, and reliability. The service delivers to around 180 countries, some of which come with money-back guarantees if date-certain delivery is important to you.

Parcel Specifications

  • Maximum weight for mailing boxes: 70 lbs.
  • Maximum combined length and girth: 108 inches

Additional Benefits

Further, Priority Mail Express International includes $100 in insurance for documents and $200 in insurance for merchandise, as well as a USPS tracking number. Given the complexity of international shipping services, having access to tracking information provides important visibility and drives customer confidence for your business.


The cost of shipping with Priority Mail Express International will vary depending on the country you’re shipping to, the size of the package, and the overall weight of the parcel. For example, let’s say you’re shipping a 5 lb package, measuring 8x8x8 inches, from New York City to London. The retail rate would be $102.70. However, Shippo users sending that same package can do so for $98.47. That’s a savings of $4.23. For e-commerce merchants who consistently ship internationally, this can quickly add up over time.

Priority Mail International

Service Profile

Like Priority Mail Express International, USPS Priority Mail International delivers to 180 countries worldwide. The trade-off is that, while shipping costs less through this service, transit times are longer, averaging 6-10 days, compared to the 3-5 days offered through Express International.

Parcel Specifications

  • Maximum weight: 70 lbs.
  • Weight restrictions may be lower for some countries.

Additional Benefits

Priority Mail International includes $100 insurance for documents, $200 insurance for merchandise, USPS tracking numbers, and return receipts. Individual shipping rates are based on the parcel’s weight and destination country; day-definite delivery is not guaranteed with this service.


Again, these packages will all vary depending on size, weight, and destination. But, we can take a look at an example to get an idea. Let’s say you’re shipping a 1 lb package, measuring 7x7x7, from Austin, Texas to Sydney, Australia. Retail rates for PMI would cost $66.20. Meanwhile, with Shippo, that package would be delivered for $63.78. That’s a savings of $2.42, which may seem small, but is something that can’t be ignored when scaling up your business.

Priority Mail International Flat-Rate

Service Profile

Both Priority Mail Express International and Priority Mail International offer flat-rate pricing as an alternative to weight-based shipping costs. Depending on the items you ship, flat-rate pricing can save you money. However, you’ll need to ensure your shipments meet both the weight and dimension requirements of the specific service and flat-rate packaging options you select to take advantage of this special pricing.

To determine whether or not flat-rate shipping makes sense for your international shipments, calculate your rates for both weight-based and flat-rate services. Retailers of small, heavy items are likely to come out ahead on flat-rate services, while those with larger, lighter offerings may see lower rates from weight-based alternatives.

Parcel Specifications

  • Maximum weight for Priority Mail Express International Flat Rate envelopes, legal envelopes, and padded flat-rate envelopes: 4 lbs.
  • Maximum weight for Priority Mail International Flat Rate envelopes and small flat-rate boxes: 4 lbs.
  • Maximum weight for Priority Mail International medium and large flat rate boxes: 20 lbs.

Additional Benefits

USPS Priority Mail International Flat Rate shipping benefits are controlled by the specific service they’re associated with. USPS  Priority Mail Express International Flat Rate shipments, for example, may be eligible for delivery date guarantees, while parcels mailed through both Express International and Priority Mail International receive insurance, tracking, and delivery receipt benefits.


Since Flat-Rate packages follow a different pricing model, you expect different rates. There are 4 categories. Flat Rate envelopes, Small Flat Rate Boxes, Medium Flat Rate Boxes, and Large Flat Rate Boxes. Priority Mail International Flat Rate envelopes shipped through Shippo start at 28.57, small flat rate boxes start at 29.64, medium flat rate boxes start at 56.10, and large flat rate boxes start at 69.10. Only Flat Rate Envelopes are available for Priority Mail Express International and those rates start at $51.98 for Shippo users.

First-Class Mail International

Service Profile

Unlike USPS Priority Mail International services, First-Class Mail International is specifically intended for mail pieces up to 15.994 oz. — not for shipping boxes or envelopes.

Parcel Specifications

  • Maximum weight for postcards and letters: 3.5 oz.
  • Maximum weight for envelopes: 15.994 oz.

Additional Benefits

There is no insurance included with First-Class Mail International mailings, though USPS tracking, registered mail status, return receipts, and certificates of mailing (for unregistered mail) are all available for purchase. Note that shipping via First-Class Mail International can be done through a Post Office branch or through a service like Shippo; it can’t be handled through the USPS website.

First-Class Package International Service

Service Profile

As with First-Class Mail International mailings, pricing for USPS First-Class Package International Service shipments is always variable based on weight and destination. This service is meant for small, lightweight packages that don’t exceed $400 in value. The maximum combined length, height, and width cannot exceed 36 inches (or 42 inches for rolls and tubes).

Parcel Specifications

  • Maximum weight: 4 lbs.

Additional Benefits

First-Class Package International Service shipments can be managed at a Post Office branch, online, or through Shippo. As with First-Class Mail International deliveries, there is no insurance included with the First-Class Package International Service. USPS tracking, registered mail status, return receipts, and certificates of mailing (for unregistered mail) are all available, and online shipments will receive a Delivery Confirmation International notification.


The shipping label rate will be determined on the same rules as that for Priority Mail International. Rates are grouped in sections based on weight. Packages weighing 1-8 oz make the first group, 12-32 oz make the next group, 36-48 make the next group, and 52-64 make the final group. This means a package weighing 2 oz or 7 oz going to the same destination would receive the same rate. To get a sense of what the rates are, let's go back to our example of shipping a parcel from Austin, Texas to Sydney, Australia. For First-Class Package International Service this parcel would cost $39.30 retail but would cost only $37.33 when shipped with Shippo.

USPS International Shipping Rules and Restrictions

Regardless of the international shipping service you choose, you’ll be subject to rules and restrictions — both from your carrier and your destination country. To ensure you remain in compliance, keep the following tips in mind:

  • As a general rule, if you can’t legally ship something in the US through the USPS, you won’t be able to ship it internationally as well.
  • Beyond this, however, some items that can be shipped in the US are prohibited from being shipped internationally. Aerosols, alcoholic beverages, cigarettes, dry ice, fresh fruits/vegetables, nail polish, alcohol-based perfumes, and poisons all fall into this category.
  • Additional items may be prohibited on a country-specific basis. The USPS’s Index of Countries and Localities is the best, most current source of this data.
  • The USPS does not deliver to any countries that are currently being sanctioned by the Office of Foreign Assets Control (OFAC), including Belarus, Cuba, Iran, Iraq, North Korea, and Syria, amongst others.

In addition, all USPS international shipments require customs documentation, while many are subject to destination-specific tax and duty fee arrangements. Shippo makes it easy to manage international shipments and prepare the paperwork required for each order.

How US Businesses Can Save Money and Time on International Shipping

US-based businesses may spend big when it comes to international shipments, but there are plenty of steps individual retailers can take to keep their costs down — including adopting a multi-carrier shipping software like Shippo.

Shippo, which is specifically designed for e-commerce businesses, works with the nation’s leading carriers to offer the best possible international shipping rates, including USPS. For instant estimates on current discounted domestic rates, sign up to Shippo for free and type in the dimensions and shipping address of your parcel.

Besides the significant cost-savings, Shippo also saves you time by allowing you to batch-process international shipping documents and labels from within a central, easy-to-use dashboard. This means you can:

  • Pre-fill customs documents
  • Create commercial invoices and packing slips automatically
  • Dynamically generate scannable return labels for hassle-free returns
  • Create manifests so that you can ship a group of packages at once

Finally, Shippo’s analytics features make it possible to keep track of your international shipping history, how much you’ve spent, and your overall efficiency so that you can continually optimize your process and realize additional cost-savings.

Using USPS for International Deliveries

Although USPS isn’t always the first option e-commerce business owners consider for their international shipping needs, it’s certainly an effective solution. USPS international delivery times can be as little as 1-3 days — even overnight for select Canadian cities. Other service lines trade slightly slower delivery times for competitive pricing that makes international shipping affordable for retailers of all sizes.

Ultimately, choosing the right service for international shipments comes down to your needs, budget, and timeline requirements. To keep your international orders organized and to save money on USPS international shipping, use a multi-carrier shipping software like Shippo to get even more bang for your international delivery buck.

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Sarah Gage
is a Michigan-based freelance writer covering business, marketing, and technology topics. She is also the owner of Content Conquered, a B2B-focused content marketing consultancy.

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