Preparing International Shipments
Size & Weight Requirements
Postcards must be rectangular to qualify for First-Class Mail® prices.
Oversized postcards will be charged as letters or large envelopes.
- Height: 3 1/2" min. / 4 1/4" max.
- Length: 5 1/2" min. / 6" max.
- Thickness: 0.007" min. / 0.016" max.
Must be rectangular to qualify for letter prices.
- Height: 3 1/2" min. / 6 1/8" max.
- Length: 5" min. / 11 1/2" max.
- Thickness: 0.007" min. / 1/4" max.
- Max. Weight: 3.5 oz.
Large Envelopes (Flats)
Must be rectangular, flexible, and uniformly thick to qualify for flat pricing.
Large envelopes that exceed size requirements will be charged the applicable First-Class Package International Service® (small packet) price.
- Height: 12" max.
- Length: 15" max.
- Thickness: 3/4" max.
- Max. Weight: 15.994 oz
If you’re not using a USPS-produced Priority Mail International® Box, the total girth (distance around the thickest part) of your package is up to 108".
The total weight of your package may not exceed 70 lbs, though, the destination country may have lower weight limits.
Restricted & Prohibited Items
Any items that are prohibited from being mailed domestically are also prohibited from being sent internationally.
- Lithium Batteries
- Medical Devices
- Medicine or Drugs
International Address & Label Formats
- Print complete and correct addresses clearly in capital letters with a pen or permanent marker.
- Do not use commas or periods.
- Mark the package “Fragile” or “Perishable” when appropriate.
- If you’re reusing a box, make sure all other addresses are covered or blacked out.
- Affix sufficient postage to avoid charges for additional postage due or delivery delay.
Additional Address InformationView Standard USPS Abbreviations
Guidelines for Addressing International Mail & Packages
Complete a Customs Form
You generally need a customs form for all international mail and parcels. You can create a customs form when using Click-N-Ship®, using the USPS Customs Forms tool, or by filling out PS Form 2976-R and taking it to a clerk at your local Post Office™ location for them to create a label.Complete a Customs Form
Pack the Box
Choose a sturdy box with enough room for cushioning material around the contents to protect fragile items and prevent items from shifting.
Tape your box shut and reinforce the seams with 2"-wide packing tape. Do not use cord, string, or twine because it gets caught in the mail processing equipment.Order Supplies
Military & Diplomatic Mail Expand Collapse FAQ question
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Full Letter Mail Standards Expand Collapse FAQ question
Meeting one or more of the following are considered nonmachinable and subject to a surcharge.
- Envelope has clasps or similar stiff closures.
- Envelope contains items causing thickness to be uneven.
- Address is written parallel to the short side of the envelope.
- Envelope is too rigid.
- The aspect ratio of the envelope (length divided by height) is less than 1.3 or more than 2.5.
- Is polybagged, polywrapped, enclosed in any plastic material, or has an exterior surface made of a material that is not paper.
- Envelopes more than 4 ¼ inches high or 6 inches long and the thickness is less than 0.009 inches.
- Is a self-mailer or booklet not prepared according to standards.
For Priority Mail International Flat Rate® Envelopes, the weight limit is 4 lbs. Large envelopes that do not meet the above standards must pay parcel prices.
Postage Payment Tips Expand Collapse FAQ question
Full Package Standards Expand Collapse FAQ question
Fragile Items Expand Collapse FAQ question