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How to Address an Envelope: Return Address, Delivery Address, and Postage Placement
Introduction
How to address an envelope sounds like something you'd figure out in five minutes. And mostly you would, except for a few things most people get wrong that silently slow their mail down or get it returned. USPS processes about 167 million pieces of mail every single day through high-speed optical character recognition equipment. That equipment is reading your envelope in a fraction of a second. It's looking for specific information in specific locations, and if what it needs isn't where it expects to find it, the piece either gets flagged for slower manual sorting or comes back to you.
This guide covers exactly where everything goes, why the placement rules exist, and what most general addressing guides skip entirely.
The Three Zones That USPS Equipment Looks For
Think of the front of a standard envelope as having three jobs to perform simultaneously: identify where the mail should go, identify where it should come back if it can't be delivered, and confirm that postage has been paid.
USPS automated sorting equipment is calibrated to find each of those in a specific location. It doesn't improvise.
Upper-left corner: your return address. This is where you go on the envelope. Your name, your address, your city-state-ZIP. The machine treats this zone as the sender identification area. A return address isn't legally required for domestic mail, but any envelope without one that can't be delivered goes straight to the USPS Mail Recovery Center. That's a building in Atlanta where pieces end up when there's nowhere to return them. Most of them don't come back. For business mail, treating the return address as optional is a mistake that comes back to bite organizations during high-volume billing runs.
Center face: the delivery address. This is the zone that OCR machines are reading. The delivery address block has to sit between 5/8 inch and 2-3/4 inches from the bottom of the envelope, centered horizontally, with at least one inch of clear space on each side. Per USPS DMM 202, those aren't suggestions. Addresses placed outside that window may fail OCR scanning and get routed to manual processing, which adds handling time and can trigger nonmachinable surcharges on bulk programs.
Upper-right corner: postage. Reserved entirely for stamps, metered postage, or permit imprints. Nothing else should appear there.
Barcode clear zone: the bottom 5/8 inch. This one surprises people. USPS automated sorting equipment prints an Intelligent Mail barcode on each piece after scanning, right along the bottom edge of the envelope face. The area is 4-1/2 inches wide by 5/8 inch tall in the lower-right area. If you have any text, design elements, borders, or printed graphics inside that zone, the barcode system can't place it correctly. The piece goes to manual sorting. For custom-printed business envelopes with full-face design work, this zone requires active planning during artwork production.
How to Address an Envelope, Step by Step
Step 1: Write Your Return Address in the Upper Left
Your name or company name goes first, followed by the street address on the next line, then city, state abbreviation, and ZIP on the last line. Keep it stacked vertically, flush left, in the upper-left area of the envelope.
JANE SMITH
456 OAK AVENUE
SPRINGFIELD IL 62704
USPS prefers all-caps and minimal punctuation on address blocks. For personal mail it's not a strict requirement, but it increases machine readability and is worth the habit. The other thing that gets people into trouble here: putting the return address on the back flap of the envelope. It feels natural, and a lot of people do it. But USPS scanning equipment reads the address side of the piece, and a back-flap return address doesn't reliably get picked up. Keep it on the front, upper left.
Step 2: Center the Delivery Address on the Envelope Face
The recipient's name goes on the first line, company name on the second if applicable, street address with unit number on the third, then city-state-ZIP on the fourth. Center the whole block horizontally on the face.
JOHN DOE
ACME CORPORATION
789 MAIN STREET SUITE 200
CHICAGO IL 60601-1234
That last part after the hyphen- the ZIP+4 code- is optional but worth including when you have it. It routes mail to a specific block face or building rather than just a general ZIP area. For businesses running volume billing programs, ZIP+4 codes on address lists can also help qualify for presort automation discounts on bulk mailings.
Step 3: Format the Address Block Correctly
USPS OCR equipment reads characters by width pattern. That's why font choice matters more than people expect. Use a non-proportional font like Courier or Courier New. Avoid bold, italic, condensed, script, or artistic fonts- especially script. A cursive or hand-lettered address style might look elegant, but the OCR machine sees it as noise. It's one of the most common reasons custom-designed business envelopes fail automated sorting.
Stick to 10 or 12-point type. Keep a uniform left margin on every line of the address block. Make sure lines don't touch or run together.
Step 4: Place Postage in the Upper-Right Corner
Stamp, metered postage mark, or permit imprint goes in the upper-right corner of the front of the envelope, at least 1/4 inch from the top and right edges. One Forever stamp covers a standard single-ounce first-class letter piece. Add postage if the contents are heavier. A postage meter imprint replaces the stamp in the same location.
Business Envelope Addressing Formats You'll Need Sooner or Later
How to Write ATTN on an Envelope
When you're sending mail to a specific person at a business address, put the ATTN line first, above the company name. Not after it, not on the same line: above it.
ATTN JANE DOE
ACME CORPORATION
789 MAIN STREET
CHICAGO IL 60601
The reason the ATTN line goes first is that USPS OCR equipment works top-down through the address block. The delivery location (the company's street address) needs to be read clearly, and stacking ATTN above the company name doesn't interfere with that. Putting it below or after the company name can confuse the machine's attempt to parse the address.
How to Address an Envelope to an Apartment
The apartment number shares the same line as the street address, abbreviated APT, after the street name.
JOHN DOE
456 OAK AVENUE APT 3B
SPRINGFIELD IL 62704
Don't put the apartment number on its own line between the street and the city-state. The whole point is that USPS wants the complete delivery line on one line for OCR reliability. A separate apartment-number line breaks up the address in a way the machine doesn't handle as cleanly.
C/O Envelope Addressing
"Care of" formatting puts the intermediary name on its own line, between the recipient's name and the delivery address.
JANE SMITH
C/O JOHNSON FAMILY
789 MAIN STREET
CHICAGO IL 60601
PO Box Addressing
Replace the street address entirely with the PO Box designation. Don't include both a street address and a PO Box on the same piece. USPS delivers to one or the other; having both creates a delivery conflict.
ACME CORPORATION
PO BOX 1234
SPRINGFIELD IL 62705
The Option That Eliminates Addressing Entirely
Here's something most addressing guides don't mention, because most addressing guides aren't written by an envelope company. For any mailing program where the recipient's address is already printed on the document going inside the envelope, a window envelope removes the addressing step entirely.
A transparent poly-film window in the lower-left area of the envelope displays the address from the enclosed document. You fold the letter so the address faces the window, insert it, and the address is visible through the film. The document handles both functions: it's the letter and the address label.
Standard window envelope position is 1-1/8 x 4-1/2 inches, placed 7/8 inch from the left edge and 1/2 inch from the bottom. That position is pre-aligned with standard invoice and billing software address block layouts from QuickBooks, Xero, FreshBooks, and most US accounting templates. Billing departments that have switched to window envelopes don't address individual pieces anymore. The software and the envelope handle it.
When both the return address and the delivery address are on the document inside, a double window envelope handles both. Two separate windows display both address fields from the document inside. No printing or labeling on the envelope face at all. This is the standard format for check mailing programs and accounts payable runs using QuickBooks, Sage, and similar accounting platforms.
What Happens When Mail Can't Be Delivered
An undeliverable piece with a return address comes back to you with a postal endorsement explaining the problem: "Attempted Not Known," "Insufficient Address," "No Such Number," "Undeliverable as Addressed." These endorsements are genuinely useful. They tell you exactly what went wrong and let you correct the record.
An undeliverable piece without a return address goes to the Mail Recovery Center. USPS holds such items and tries to identify the sender for a set period. Items that can't be identified are auctioned or disposed of. They don't come back.
For business programs where deliverability rate matters at volume, the right preventive step is address validation before printing. USPS CASS-certified address validation software checks address lists against the USPS database, standardizes formatting, appends ZIP+4 codes, and identifies bad addresses before a single envelope gets printed. For organizations running monthly billing cycles or quarterly solicitation programs, that validation step is what keeps return rates from quietly eroding delivery performance over time.
How the #10 Envelope Handles This Workflow
The standard #10 business envelope at 4-1/8 x 9-1/2 inches gives the most room to work with of any standard commercial letter format. The delivery address block sits comfortably in the USPS-required placement zone with clear space above and below it. It's the format where addressing errors show up most visibly, which is exactly why getting the zone placement right on a #10 matters.
For #9 envelopes used as return pieces inside an outgoing #10 mailer, the addressing almost always happens at the production stage. The organization's return address is printed on the #9 face before the envelopes ship. The recipient gets a pre-addressed return piece and just needs to insert their response and seal it. That's how billing programs, nonprofit donation campaigns, and membership renewal mailers handle the return piece- not by having someone address each one manually.
Custom logo and return address printing is available on every envelope format at Business Envelopes, with no minimum order. Pre-printed envelopes mean your team isn't addressing individual pieces by hand on outgoing mail. For recurring programs, the return on that is immediate. Request a quote to price a custom print program across your full envelope lineup.
Conclusion
Addressing an envelope correctly takes about thirty seconds once you know the layout. Return address upper left, delivery address centered in the USPS placement zone, postage upper right, barcode zone at the bottom clear. The rules behind each of those positions exist because 167 million pieces move through automated equipment every day and the machine finds what it needs by looking in the same spot every time. For personal mail, learning the layout once is all it takes. For business programs running consistent document formats at volume, a window envelope that handles addressing automatically is almost always the better answer. Business Envelopes has supplied both formats since 1997, blank or custom printed, with free shipping and no minimum order on every size.
FAQs
Where does the return address go on an envelope?
Upper-left corner of the front of the envelope. Your name or company name, then street address, then city-state-ZIP, stacked vertically. Don't put it on the back flap- USPS equipment reads the front only.
Where does the delivery address go on an envelope?
Centered horizontally on the envelope face, within the USPS placement zone: top of the address block no more than 2-3/4 inches from the bottom edge, bottom of the address no less than 5/8 inch from the bottom edge, with at least one inch of clear space on each side.
Where does the stamp go on an envelope?
Upper-right corner of the front, at least 1/4 inch from the top and right edges. That space is reserved for postage only.
What is the barcode clear zone on an envelope?
The bottom 5/8 inch of the envelope face, full width, must be left completely empty. USPS automated sorting equipment prints an Intelligent Mail delivery barcode in that area during processing. Any text or design inside that zone interferes with barcode placement and pushes the piece to manual sorting.
How do you write an apartment number on an envelope?
On the same line as the street address, abbreviated APT: "456 OAK AVENUE APT 3B." Don't put the apartment number on its own line. USPS OCR equipment reads the complete delivery address on one line and a separate apartment-number line breaks up that read.
What does ATTN mean on an envelope and where does it go?
ATTN identifies a specific person at a business address. It goes on the first line of the address block, above the company name: ATTN JANE DOE on line one, then the company name, then the street address, then city-state-ZIP.
Is a return address required by USPS?
Not legally required for domestic mail, but strongly recommended. Pieces that can't be delivered without a return address go to the USPS Mail Recovery Center and may be disposed of if the sender can't be identified.
What is a window envelope and how does it avoid the addressing step?
A window envelope has a transparent film panel on the face that displays the recipient's address from the document inside. No addressing on the envelope is needed- fold the document so the address faces the window, insert it, and the address shows through.