How To Address an Envelope Properly

Table of Contents
Best Practice
Domestic Addresses
Post Office
Military Addresses
Military Address Examples
U.S. Postal Abbreviations
International Addresses
International Addresses Examples
Provinces & Postal Codes
Addressing Letters to More Than One Recipient
When to use Attn: or C/O
All About Address Stamps
Address Tips

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’ve used the right address format, you won’t have to fret about whether 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.

Self-inking address stamp laying on envelope next to a planner and elegant pen

Self-inking address stamp laying on envelope with floral background

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 address formatting, and a step-by-step guide on how to address an envelope. 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 formats. You will also discover links to more helpful resources if you have questions.

Best Practice To Prevent Lost Mail

Ever wondered if you must have a return address on your letter to mail it? The answer is no. While this is not a requirement set by the postal service, it helps to prevent undeliverable mail from being misplaced. Undeliverable mail means that the lack of a return address or improperly formatted address will make it impossible to have the letter get back to the intended owner or sender, and may be lost. The USPS reports that 25% of all mail items have an improperly formatted address. There are a few simple practices that can ensure your mail is written and sent out correctly.

Make sure you know how to pluralize names when you write an 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.

Envelope with Return Address Stamped on

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 poorly formatted 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.

Get 20% Off with Code SIMPLY20, Custom Doberman Return Address Stamp on Envelope

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 member’s 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

Official State Abbreviations

In order to properly fit a city, state and zip code on one line, official two-letter state abbreviations are commonly used in envelope addressing. When learning how to address an envelope, it’s important to use the correct state postal abbreviation to ensure that your mail makes it to the right destination.

Here are the official U.S. Postal Abbreviation Guidelines to use when addressing letters:

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 address formats for provinces and postal codes.

This City Line Table comes from

Addressing a Letter to More than One Recipient

Letters with more than one recipient need to be addressed following the appropriate guidelines. Here’s a helpful guide on how to address an envelope to a family unit, married couple, and groups with different last names:

For family units, you can refer to your recipients as a collective group. For example,

The Recipient Family
Street Address or P.O. Box
City, State Abbreviations, Zip

To send a letter to a married couple with the same last name, address the couple using their titles (“Mr.”, “Mrs.”, “Dr.”, “Rev.”, etc.) followed by their shared name.

Mr. and Mrs. Recipient’s Shared Last Name
Street Address or P.O. Box
City, State Abbreviations, Zip

For married or unmarried couples or groups with different last names, fully address your letter with both names written out on one single line.

Ms. Recipient 1 and Mr. Recipient 2
Street Address or P.O. Box
City, State Abbreviations, Zip

Addressing a Letter with Attn: or C/O:

Attn: and C/O are used when addressing a letter to a recipient through an organization, a business or a specific person.

How to Address a Letter with Attn:


Stands for “attention” Most personal correspondence and letters do not require an attention attribute. “Attn:” is used when your letter is being sent to a company, a department, an organization, a business, etc. but is intended for an individual or individuals within the group.

For example,

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

How to Address a Letter with C/O:


Stands for “care of”. C/O is used when sending mail to a recipient who is in the care of another individual. This is commonly used when a person is temporarily staying at a certain address for a short amount of time.

Here is how to format an address with C/O:

Recipient Name
C/O Name of Person/ Organization who the recipient is in the care of
Street Address or P.O. Box
City, State Abbreviations, Zip

About Address Stamps

example return address stamps

How Address Stamps are Beneficial

Learning how to address an envelope is important for making sure your mail makes it to the correct destination, and for making sure that it can find it’s way back to you if returned. Want to skip the hassle of adding your return address to each and every letter and correspondence? Address stamps are a convenient and easy way to ensure your mail has the proper return address. Here are just some of the ways that return address stamps can take the hassle and stress out of addressing your mail:

  • Proper Address Formatting: Return address stamps ensure that your return address is consistently spelled and formatted on all of your outgoing letters, mail and correspondence.
  • Easy Customization: At Simply Stamps, our return address stamps are easy to customize in just a few simple steps. Add your name and address in the corresponding fields before placing your order and we’ll take care of the rest! Your stamp will be customized according to your specifications, then shipped out from our facilities fast!
  • Crisp, Clear Impressions: Don’t worry about unclear handwriting and ensure that your return address is legible. Address stamps provide a consistent, clear impression every time.
  • Quick & Efficient Addressing: Skip the hassle of repetitively writing out your return address on every envelope and outgoing piece of mail. Our return address stamps are an efficient way to quickly address correspondence with minimal effort.
  • Stylish Designs: Our custom address stamps are available in a variety of designs for weddings, holidays, states and more. Find your favorite design to send out your mail in style.

Using Stamps to Ship & Address Packages

Return address stamps are not just for mail! They can also be used on small packages and shipping labels. At Simply Stamps, we specialize in creating custom return address stamps that simplify shipments for both professional and personal use.

With options ranging from custom logo address stamps to monogram address stamps, our personalized stamps are a convenient tool for all of your outgoing packages. Here are some of the top ways that custom address stamps can simplify your shipping processes:

  • Address stamps are a budget-friendly solution that prevents the need to order expensive shipping labels.
  • Custom logo and professional address stamps can ensure that all of your business shipments are accurately addressed.
  • Rubber stamps are easy-to-use and can help create a streamlined and efficient shipping process.
  • Address stamps take the stress and time out of addressing outgoing shipments. You can correctly address your packages in a matter of seconds.

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
  • Be sure to check the latest guidelines and tips on how to address an envelope before sending out any correspondence!
  • 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.