How To Address Envelopes Properly

Correctly formatting the mailing address on any letter you send out can help get your mail to its recipient as quickly and efficiently as possible. If you know you have written an address properly, you won’t have to fret about whether or not your letter will arrive or get lost once you’ve dropped it in your mail box.

After you have your letter ready to go with the contents, return address stamp and postage stamp, take an extra moment to ensure that you have followed the requirements for writing addresses.

Little errors can slow your mail down. Bigger errors can keep it from reaching the destination. Here is a brief summary of some of the basic requirements for domestic and international addresses. You can also review tips for sending letters to those who are deployed in the Military. This is not a comprehensive guide, but covers many essential areas regarding proper address standards. You will also discover links to more helpful resources if you have questions.

Best Practice To Prevent Lost Mail

Always include a return address in the upper left hand corner. While this is not required by the postal service, it prevents undeliverable mail from being lost. The USPS reports that 25% of all mail items have something wrong with the address

It can be easy to leave off an apartment number or put an incorrect zip code. Make sure to double check the address you write and make sure details like the state abbreviation and zip code are correct.

Many mail pieces do not include directional information like East or West, which disrupts routing and delivery. Directional information includes N, S, E, W, NE, NW, SE, and SW. For street names, directionals should be abbreviated. For city names, directionals should be spelled out. Directionals are often found in the street address line, and may be before or after the street name. The bottom line with this component is to make sure each is included. A single letter can send mail to an entirely different destination.

While the Postal Service may still be able to deliver to the incorrectly written address, it will take longer and is not guaranteed. To ensure each mail piece gets to its destination in a timely manner, and can be returned to its sender, make sure to include the return address.

Domestic Addresses

The basic address format in the United States includes a minimum of 3 lines.

Format for a Basic address in the U. S.:

Recipient’s Name
Street Address
City, State Abbreviations, Zip

Format for Including a Business Name:

Recipient’s Name
Company Name
Street Address or P.O. Box
City, State Abbreviations, Zip

Format for Longer Street Addresses that Include Suite/Apartment Numbers:

Recipient’s Name
Apt #1234
Street Address
City, State Abbreviations, Zip  advises that when the apartment number doesn’t fit on the street address line, apartment number should be written ABOVE the street information. The USPS prefers including the apartment number on one long street address line, but also suggests the alternative of including an apt line above the street address.

This can be confusing as many online form fields include a 2nd address line for apartment and suite information. Many people have gotten in the habit if writing apartment numbers underneath the street address. Fortunately, mail can still be processed with the apartment line written under the street information. These guidelines are designed to assist with sorting and delivery efficiency.

Post Office Box Options

There are two ways that P.O. Box information can be conveyed.

Recipient’s Name
PO BOX 67702
Tucson AZ 85728

Recipient’s Name
POB 67702
Tucson AZ 85728

The Military P.O. Box guidelines include additional requirements.

Military addresses

Military addresses  for those who are deployed internationally should follow a specific format. Here are the main components of a military address:

  • The first line must include the service members name
  • The second line must include the unit and Box
  • The third line includes the following abbreviations and the zip code.

The city line begins with APO (Air/Army Post Office), FPO (Fleet Post Office), or DPO (Diplomatic Post Office). Only the abbreviation is included. Where the state would normally be listed, you will include one of the following abbreviations AE (Armed Forces), AFP (Armed Forces Pacific), or AFA (Armed Forces America).

These do not include the country destination. Instead, the fourth line is left blank.

Examples of Military Addresses:

Army/Air Post Office (APO):
PSC 3 BOX 4120
APO AE 09021

Fleet Post Office (FPO):
UNIT 100100 BOX 4120
FPO AP 96691

Diplomatic Post Office (DPO):
UNIT 8400 BOX 0000
DPO AE 09498-0048

Two International Addresses Differences

International addresses should be formatted based on recommendations from the destination country. Upper and lower case requirements, punctuation, postal codes and province rules may vary. Always be sure to check each destination’s requirements before sending.

While there are some variants in the address requirements from country to country, there are 2 consistent differences. These exist in the last line, and the 3rd line (also known as the city line). The first thing you will notice is including the name of the destination country as the last line of the address.

Use the U.S. name of the country from the IMM. For example, write Germany, not Deutschland. Explores a full list of country names provided by the USPS here.

Basic International Format

Recipient’s Name
Street Address
City, town, province, county or other designation
Postal Code
Country Name

Recipient’s Name
Street Address
City, town, province, county or other designation, AND postal code
Country Name


James Henry
1450 Carlyle Road
London WIP 8HQ

Provinces & Postal Codes

The 3rd line may contain region names for a state, province, county, district, town, territory, land, shire, department, canton, prefecture, oblast or autonomous region. In most countries the city line goes below the street address, however, in Hungary the city line goes before the street address. There may be additional exceptions.

Some countries include the postal code at the beginning of the 3rd line while others include it at the end. Still, other countries prefer the postal code to be listed on a line by itself.

Here is a summary of some of the formats for provinces and postal codes.

This City Line Table comes from

Final Addressing Tips

The United States Postal Services publishes an International Mail Manual, which is updated with the newest changes. Checking this document may assist with any questions you may still have.

As a quick reminder:

  • When you send letters internationally, include the United States as the last line of the return address.
  • The USPS suggests writing in capital letters to provide the greatest amount of clarity.
  • Addresses should comply with guidelines from both the sender’s country and the destination country.

Address formats are updated periodically, so always double check the postal requirements before sending to an international destination.



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