How to Address an Envelope
Address an envelope the way USPS sorting machines read it, with the return address, delivery address, apartment number, and stamp in the right places, plus business, international, and PO box formats.
You will end up with an envelope addressed the way the US Postal Service's sorting machines read it: your return address top left, the delivery address in the bottom center, the apartment number on the right line, the stamp top right, and the barcode area clear.
The format follows the Postal Service's addressing standard, Publication 28, which is written so its automated sorting machines can read the address. An address the machines cannot read can be delayed or returned.
The steps cover domestic US mail. The FAQs below cover businesses, international mail, someone staying at another person's house, and PO boxes.
An envelope (standard #10 business size or A2/A7 greeting card size). A pen or permanent marker with dark ink, such as black. 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, and FAQ 3 below explains what happens without one.
Write the recipient address in the bottom 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. Line up every line on the same left edge, which is how the addressing standard formats the address block. 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, so CA rather than Ca. or Calif., and NY rather than N.Y. Include the full 9-digit ZIP code (ZIP+4) if you know it, because it narrows the delivery point for the sorting machines.
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, the postal standard puts the unit number on the line immediately above the street address, not below it. The same section asks you to write APT or STE rather than a pound sign when you know the right word, and to leave a space after the sign if you do use one. Keep the street address itself on the line directly above the city, state, and ZIP code, because that is the line the Postal Service delivers to.
Place the stamp in the top right corner
A First-Class Mail Forever stamp goes in the upper right corner of the envelope. Put it on last, as USPS suggests, so a mistake anywhere else does not waste a stamp. One Forever stamp covers a rectangular letter up to 1 ounce, which USPS puts at about 4 sheets of printer paper in a business envelope. USPS's letter-mailing page lists what costs more. Letters up to 3.5 ounces need extra postage for each additional ounce, and envelopes that are square, vertical, rigid, or lumpy, or have clasps, string, or buttons, pay the nonmachinable price. Check usps.com for the current prices, or take the envelope to a Post Office counter to have it weighed.
Write clearly and use dark ink
The USPS uses automated optical character recognition (OCR) to read addresses and sort mail. Use a pen or permanent marker, as USPS asks, in black or another dark color so the address stands out against a light envelope. Never use pencil, which the international mail rules reject outright. All capitals are preferred by the USPS for machine readability, though clear mixed case also works. Print in block letters, not cursive. USPS tells letter writers to print in capitals and to skip commas and periods, and the addressing standard makes exactly one exception. Punctuation may be left out everywhere except the hyphen in the ZIP+4 code. If your handwriting is difficult to read, print a label instead.
Leave the bottom area clear for postal barcodes
The USPS prints a routing barcode near the bottom of envelopes during processing, and the standard defines the space it needs precisely. The barcode clear zone is the lower right corner of the address side, running 4-3/4 inches in from the right edge and 5/8 inch up from the bottom. That requirement is written for bulk automation mailings rather than for a single letter, but the same machines handle your envelope, so the simple habit is to keep the whole bottom 5/8 inch 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 applying or reading the barcode.
If a letter comes back to you, check the line directly above the city and state first, because that is the line the Postal Service delivers to, then the apartment number, the ZIP code, and the postage for the envelope's weight and shape in step 4. If you send mail often, a return address stamp or a sheet of printed return address labels keeps the format the same on every envelope. If the envelope carries a check, our guide on how to write a check shows how to fill it out so nobody can change the amount.
Questions we get asked about this
Answers from experience, not a textbook.
Put the company name on line 1. If you are sending it to a specific person, add their name on a line above the company name ("Attn: John Smith" or just "John Smith"), which moves the company to line 2. 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.
Write every line in capital letters, with the city and postal code together and the country alone on the last line, written in full with no abbreviation. That is the rule in the USPS International Mail Manual. For example, the last two lines of its UK example read "LONDON W1P 6HQ" and "UNITED KINGDOM". Use the destination country's postal code, not a US ZIP code. The order of the city and postal code follows the destination country. The USPS example for Mexico puts the postal code first ("46807 PUERTO VALLARTA JALISCO"), and mail to Canada needs two spaces between the province abbreviation and the postal code. Look up the destination country's own format rather than assuming it matches the UK. Keep your return address in the upper left corner as usual. International postage costs more than domestic, so check usps.com for the rate to your destination.
Not for an ordinary letter. USPS requires one only in specific cases, such as mail with a printed service endorsement and international mail that carries a customs form. Include one anyway. 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.
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 that the letter is for Michael Brown and goes to Jane Smith's address.
Yes. USPS mailing standards ask for at least 8 point type and prefer a sans-serif font, which a printed label meets more reliably than handwriting does. You can print labels from most word processors. Avery 5160 labels, 1 by 2-5/8 inches and 30 to a sheet, fit a four-line address. Use a sans-serif font such as Arial at 10 point or larger, which keeps the text well above the 8 point minimum. 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.