How to ship internationally with USPS comes down to three choices: pick the right service for the weight and deadline, fill out the customs form correctly, and measure and weigh the box before you buy the label. Get the customs form wrong and the package can stall in customs or come back at your expense.
How to ship internationally with USPS: services compared
USPS offers three main international parcel services. Ground Advantage is domestic only.
| Service | Best for | Typical transit | Starting retail price |
|---|---|---|---|
| First-Class Package International Service | Light, low value orders | Varies by destination, often 2 to 5 weeks | From $19.40 |
| Priority Mail International | Heavier orders or a firmer deadline | 6 to 10 business days | Flat rate envelope from $32.65 |
| Priority Mail Express International | Urgent orders | 3 to 5 business days | From about $62.70 flat rate envelope (varies) |
First-Class Package International Service is the budget pick, but it has hard limits: packages up to 4 lbs and up to $400 in declared value. Anything heavier or worth more needs Priority Mail International or Express. Priority Mail International also has flat rate boxes, small from $33.75, medium from $61.80, and large from $75.15 at retail, which win when contents are heavy for their size.
Worked example: a 2 lb order to Canada and the UK
Say you sell a cotton t-shirt worth $40, packed in a 9 x 6 x 3 inch box weighing 2 lbs. Commercial rates pulled in 2026 put that shipment at about $27.65 to Canada by First-Class Package International, $45.51 by Priority Mail International, and $68.92 by Priority Mail Express International. To the UK the same box runs about $33.98 by First-Class Package International and $74.42 by Priority Mail International. The economy service costs roughly half the express service but adds weeks.
Customs forms: which form and how to fill it out
Every international package needs a customs form, and the form depends on the service. First-Class Package International shipments valued at $400 or less use the short form, PS Form 2976. Priority Mail International uses the longer PS Form 2976-A. Use USPS Click-N-Ship, which creates the label and customs form together, or the Customs Form Online tool. Handwritten customs forms are no longer accepted.
On the form, describe every item specifically, not with a generic word. Write "men's cotton crew neck t-shirt, size large" instead of "clothing", and list each item separately with its own value. The total must equal the sum of the item values. Since September 1, 2025, commercial shipments must also carry a six digit Harmonized System (HS) code per item, but USPS tools assign it from your detailed description, so you do not need to look it up yourself. Vague descriptions are the most common reason a package gets held.
Duties, taxes, and the 2026 EU change
Duties and taxes are usually the buyer's responsibility unless you choose to pay them, and they depend on the destination country's rules and the declared value. Two recent changes catch sellers out: duty free thresholds have tightened in several destinations in 2026, and starting July 1, 2026, packages valued up to 150 euros sent to EU countries face new import duties and requirements. State in the listing that the buyer pays any import charges. Surprise duty bills are a top cause of international returns and bad reviews.
Pack, measure, and weigh before you buy the label
International postage is priced by weight and destination, and some services also consider size, so a wrong measurement means a wrong label and a possible surcharge or return. Weigh the packed box on a scale, not by guessing, and measure the packed box, not the product. Round weight up to the next ounce for First-Class Package International. Check USPS service alerts for your destination before you ship, since service to some countries is suspended from time to time, and confirm your product is allowed: aerosols, perfumes, and lithium batteries are restricted or prohibited internationally even though they ship fine domestically.
Measure your box first, then pick the cheapest service
The cheapest international service is the one that fits your actual box, not the one with the lowest starting price. A heavy box that fits a small flat rate box can beat a weight based price, while a light box in an oversized carton wastes money on every order. Open our free box size calculator, enter your packed box dimensions, and check the size and weight before you compare USPS services or buy a label.
Quick answers
What is the cheapest way to ship internationally with USPS? For packages under 4 lbs worth $400 or less, First-Class Package International Service is usually cheapest, from $19.40 retail. Which customs form do I need? PS Form 2976 for First-Class Package International up to $400, and PS Form 2976-A for Priority Mail International, generated electronically. Do I need an HS code? Yes for commercial shipments, one six digit code per item, assigned by USPS tools from your description. How long does it take? Priority Mail International runs 6 to 10 business days, Express International 3 to 5 business days, and First-Class Package International typically 2 to 5 weeks.
Rates above reflect USPS published prices and 2026 commercial rate examples as checked in November 2026. Rates vary by destination, weight, and price group, so confirm current rates and service availability for your destination before you price a product or buy a label.
