Learn how to send letters and packages internationally. USPS® can help you address international mail, fill out customs forms, find out what you may send to Canada and other countries, and tell you where you can drop off your shipment. Preparing your package and mailing it properly helps it arrive on time and saves you money.

For mail and packages sent domestically, see Sending Mail and Sending Packages.


ALERT: USPS can no longer accept or deliver international mail to several countries due to COVID-19 service impacts. See all countries with temporary service and guaranteed-delivery suspensions. Read More

What may you mail to other countries? Anything that may not be sent within the United States may not be sent internationally. Many countries have additional prohibitions to obey.

Step 2: Check Allowed Size & Weight

Make sure that youre using standard sizes for your envelopes and boxes. If your mail item cant fit through automated processing equipment, it is considered nonmachinable and costs more to send.

Items 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.

Large envelopes that do not meet the above standards must pay parcel prices. For Priority Mail International Flat Rate® Envelopes, the weight limit is 4 lbs.

Pack your box to protect your contents and to make sure the box arrives intact.

  • Use a sturdy box with enough room to add cushioning for fragile items and to prevent items from shifting.
  • Tape your box so that it closes flat on all sides and reinforce the flaps with 2-inch wide packing tape.
  • If youre reusing a box, make sure all old logos, shipping labels, and addresses are covered or blacked out.

Shipments sent in Priority Mail International® Small Flat Rate Priced Boxes can weigh up to 4 lbs.

  • Shipments sent in Priority Mail International Medium and Large Flat Rate Boxes can weigh up to 20 lbs.
  • Packages shipped via First-Class Package International Service® must weigh 4 lbs or less and have a value of $400 or less.

Order Shipping Supplies

Step 3: Address Your International Mail

Write or print your return address and the address youre mailing to clearly in the correct spots to make sure your mail is delivered on time.

  • Print complete and correct addresses clearly in capital letters.
  • Use a pen or permanent marker.
  • Do not use commas or periods.
  • Mark the package Fragile or Perishable when appropriate.
  • If youre reusing a box, make sure all other addresses are covered or blacked out.
  • Include sufficient postage to avoid charges for additional postage due or delivery delay.

How to Address International Mail & Packages

To prevent mail from entering foreign mail networks, do not include city or country names in APO/FPO/DPO shipping addresses. Make sure you include the unit and box numbers for APO/FPO/DPO shipping addresses (if assigned).

Military Address Examples

International shipments can be sent via Global Express Guaranteed®, Priority Mail Express International®, Priority Mail International®, First-Class Mail International®, First-Class Package International Service®, or Airmail M-Bags®.

  • Package contents
  • Destination
  • Delivery Speed
  • Shape, size, and weight
  • USPS Tracking®
  • Special handling and insurance
  • Delivery confirmation receipts

See All International Mail Services

The International Mail Manual will let you know which services can be used when shipping to a particular country.

Individual Country Listings

Add insurance or other extra services depending on the mail service you choose. Ordinary items that are breakable or fragile do not need special handling if they are packed with the right cushioning and marked clearly with the word, FRAGILE. You may add Registered Mail® to your delivery to further protect valuable or irreplaceable items.

International Insurance & Extra Services

Step 5: Create Customs Forms & Labels

You are required to fill out a customs form when shipping internationally, except when sending non-negotiable documents or correspondence weighing under 16 oz via First-Class Mail International.

When you print your international postage with Click-N-Ship®, our tool automatically creates the necessary customs form for you.

Print a Label

If you are not using Click-N-Ship and just need to fill out a customs form, our online tool will walk you through the process.

Create a Customs Form

Dont forget you will need a customs form for sending shipments to military bases and embassies outside of the United States, despite paying only domestic prices.

Learn about Military & Diplomatic Mail

Step 6: Calculate & Apply Postage

Correct postage helps your packages arrive on time. Shipping costs depend on several factors. You can enter your package information into the USPS Postage Calculator to get international postage prices for different services.

Underpayment can result in the recipient being charged for postage due and may delay delivery. Avoid underpayment by:

  • Rounding up on weights. USPS rounds up to either the lb or oz. For example, if your package weighs 3 lbs 5 oz, it would be charged at the 4 lb-rate. This applies to all mail classes.
  • Verifying the mail class. For example, First-Class Mail can only be used for packages 10 oz and under.
  • Checking the dimensions. Dimensional weight may apply to your package, so always enter a packages dimensions to ensure you are accurately charged.
  • Using the correct package label. Make sure the label youre using matches the packaging.

Calculate a Price

Step 7: Send Your Shipment

Where to mail your box depends on its size and how youre paying for postage. You can drop small packages in a blue collection box, visit your local Post Office location, or request free package pickups on certain items.

  • If your mailpiece weighs 10 oz or less and has the correct postage, give it to your carrier or drop it off in a blue collection box or a Post Office lobby drop.
  • If you have a mailpiece with a customs form that was not completed and submitted online or any mail item that requires a customs form and bears postage, you must take it to a Post Office retail counter to mail it. If you put it in your mailbox, the carrier will leave it there. If you drop it in a blue collection box or lobby drop, it will be returned to you.

Post Offices & Drop-Off Locations

Your letter carrier can pick up your international packages if youve completed the shipping label and customs from and paid for the postage online. Here are the international services eligible for pickup:

  • Global Express Guaranteed®
  • Priority Mail Express International®
  • Priority Mail International®
  • First-Class Package International Service®

Free Package Pickup

Package Pickup during regular mail delivery is free regardless of the number of items scheduled for pickup. USPS usually picks up your package on the next delivery day or another designated day.

Pickup on Demand®

If you want your packages picked up at a specific time, for a fee, the Post Office will pick up your shipment within a scheduled 2-hour period.

Schedule a Pickup

Quickly see the standard sizes for international postcards, envelopes, flats, and packages.

Expand All

  Shape Size Requirements Additional Fees

Must be rectangular to qualify for letter prices.

  • Height: 3 1/2″ min. to 6 1/8″ max.
  • Length: 5″ min. to 11 1/2″ max.
  • Thickness: 0.007″ min. to 1/4″ max.
  • Max. Weight: 3.5 oz


Large Envelopes (Flats)

Must be rectangular, flexible, and uniformly thick to qualify for flat pricing.

  • Height: 12″ max.
  • Length: 15″ max.
  • Thickness: 3/4″ max.
  • Max. Weight: 15.994 oz

Large envelopes that exceed size requirements will be charged the applicable First-Class Package International Service® (small packet) price.


Postcards must be rectangular to qualify for First-Class Mail® prices.

  • Height: 3 1/2″ min. / 4 1/4″ max.
  • Length: 5 1/2 ″ min. / 6″ max.
  • Thickness: 0.007″ min. to 0.016″ max.

Oversized postcards will be charged as letters or large envelopes.


If youre not using a USPS-produced Priority Mail International® Box, the total girth (distance around the thickest part) of your package is up to 108″. Learn to Measure Package Girth


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