How to Address an Envelope
How to properly address a mailing envelope so it arrives where it should. Formatting, placement, return address, and special situations.
Addressing an envelope seems like it should be obvious. But the first time you actually need to send a physical letter, you realize you are not sure where the return address goes, how to format the recipient's address, or whether apartment numbers go on the same line as the street.
The US Postal Service has specific formatting guidelines that help their automated sorting machines read addresses correctly. A properly formatted envelope gets delivered faster and with fewer errors. An improperly formatted one can be delayed, returned, or delivered to the wrong address.
This guide covers the standard format for domestic US mail. The same principles apply internationally, with a few additions covered in the FAQs.
An envelope (standard #10 business size or A2/A7 greeting card size). A pen with dark ink (black is best for machine readability). The full mailing address of the recipient. Your own return address.
Write the return address in the top left corner
Your return address goes in the upper left corner of the front of the envelope. Write it in three lines. Line 1 is your full name. Line 2 is your street address (including apartment or suite number). Line 3 is your city, state abbreviation, and ZIP code. For example, Jane Smith on line 1, 123 Oak Street Apt 4B on line 2, Portland OR 97201 on line 3. The return address tells the post office where to send the letter if it cannot be delivered. Omitting it means undeliverable mail goes to the Dead Letter Office instead of back to you.
Write the recipient address in the center
The recipient's (delivery) address goes in the bottom center of the envelope. Use the same three-line format. Line 1 is the recipient's full name. Line 2 is their street address. Line 3 is their city, state abbreviation, and ZIP code. The USPS prefers standard abbreviations (AVE, ST, BLVD) for machine readability, though spelled-out forms are also accepted. The address block should be positioned so there is clear space above, below, and to each side.
Good to know: Use the two-letter state abbreviation in all caps without a period. CA not Ca. or Calif. NY not N.Y. The postal service sorting machines are optimized for these standard abbreviations. Include the full 9-digit ZIP code (ZIP+4) if you know it. It speeds delivery.
Handle apartment and suite numbers correctly
Apartment, suite, unit, and floor numbers go on the same line as the street address when they fit. For example, "456 Elm Street Apt 12" or "789 Commerce Blvd Suite 300." If the line is too long, put the apartment or unit number on a separate line directly above the street address. The post office reads addresses from the bottom up, so the street address should always be on the last line before the city and state.
Place the stamp in the top right corner
A standard first-class stamp goes in the upper right corner of the envelope. Current first-class stamp rates vary, so check usps.com for current pricing. For oversized, heavy, or irregularly shaped envelopes, you may need additional postage. A standard letter weighing up to 1 ounce uses one stamp. Each additional ounce requires extra postage. If you are unsure about postage, take it to the post office counter and they will weigh it and apply the correct amount.
Write clearly and use dark ink
The USPS uses automated optical character recognition (OCR) to read addresses and sort mail. Dark ink on a light envelope gives the machines the best contrast. Black ink is ideal. Blue ink works fine. Avoid red ink, light colors, or pencil, which can be difficult for machines to read. All capitals are preferred by the USPS for machine readability, though clear mixed case also works. Block letters are easier for machines to read than cursive. Skip commas and periods entirely. The only punctuation the USPS wants is the hyphen in a ZIP+4 code. If your handwriting is difficult to read, consider printing a label instead.
Leave the bottom area clear for postal barcodes
The USPS prints a barcode on the bottom of envelopes during processing. Leave the bottom five-eighths of an inch of the envelope completely clear. Do not write anything, place stickers, or add decorations in this zone. The barcode is what the sorting machines use to route the letter to the correct delivery location. Anything printed in this area can interfere with barcode application or reading, causing the letter to be sorted manually, which slows delivery.
A properly addressed envelope takes about 30 seconds to write. The format is the same whether you are sending a bill payment, a birthday card, or a formal letter. Write clearly, use dark ink, and follow the three-line format. The postal service handles the rest. If you send mail frequently, consider getting a return address stamp or printed return address labels. They save time and ensure consistency. Most office supply stores sell custom return address stamps for under $15.
Questions we get asked about this
Answers from experience, not a textbook.
Use the company name on line 1. If sending to a specific person, add their name on a line above the company name ("Attn: John Smith" or just "John Smith"). The street address goes on the next line, and city, state, ZIP on the last line. For example, Attn: Sarah Johnson on line 1, Acme Corporation on line 2, 500 Main Street on line 3, Chicago IL 60601 on line 4.
Follow the same format as domestic mail, but add the country name in all capitals on the last line, below the city and postal code. Use the destination country's postal code format (not US ZIP codes). Write the country name in English. For example, the last two lines might read "London W1A 1AA" and "UNITED KINGDOM" on the line below it. In most European countries, the postal code goes before the city name rather than after it. You would write "75001 Paris" for France or "10115 Berlin" for Germany. Some countries also expect the sender address on the back flap of the envelope rather than the front, though placing it on the front still works for outbound US mail. International postage rates are higher than domestic. Check usps.com for current rates by destination.
It is not legally required for personal mail, but it is strongly recommended. Without a return address, mail that cannot be delivered (wrong address, recipient moved, insufficient postage) goes to the USPS Mail Recovery Center (Dead Letter Office) instead of back to you. The contents may be opened to attempt to identify the sender. Including a return address costs nothing and ensures you get the letter back if delivery fails.
Write the recipient's name on line 1 and add "c/o" (care of) followed by the householder's name on line 2. The rest is the standard address format. For example, Michael Brown on line 1, c/o Jane Smith on line 2, 789 Pine Road on line 3, Austin TX 78701 on line 4. This tells the mail carrier to deliver to Jane Smith's address but that the letter is for Michael Brown.
Yes, and the postal service actually prefers them for readability. You can print labels from most word processors. Use standard Avery label sizes (Avery 5160 is common for addresses). Use a simple sans-serif font at 10 to 12 point size. Center the address block on the label. Printed labels are especially useful if you send mail frequently, have difficult handwriting, or are sending formal correspondence where neatness matters.
Write "PO BOX" followed by the box number on the delivery address line, where the street address would normally go. The city, state, and ZIP code go on the line below it as usual. If you include both a street address and a PO Box on the same envelope, the mail goes to whichever one appears on the line directly above the city and state. Make sure the ZIP code matches that delivery line.