Correctly Addressed

The complete guide

How to address an envelope

Write the delivery address in the center of the envelope: name on the first line, street and any unit number on the second, city, state and ZIP on the third. Put your return address in the top left corner and the stamp in the top right. Use dark ink, skip all punctuation, and keep the bottom strip of the envelope clear for the sorting barcode.

Checked July 29, 2026/9 min read

What is on this page5 sections
  1. 01The four zones
  2. 02The five steps
  3. 03Formatting rules
  4. 04Every situation
  5. 05Questions people ask

The four zones on an envelope

A sorting machine photographs the front of your envelope and reads it in fixed places. Learn the four places and everything else on this site is just detail.

The four zones on a No. 10 envelopeA standard business envelope showing where the return address, postage, delivery address and barcode clearance area belong.Return addressA MERCER88 PINE GROVE RDITHACA NY 14850PostageDelivery addressJORDAN REYES1420 N BROADWAY APT 4BDENVER CO 80202Barcode clearance
Drawn to scale on a No. 10 envelope, 9.5 by 4.125 inches. Measurements follow USPS Publication 28.

Tap a zone to read the rule

  • Return address

    Top left, 0.25 in margin

    Top left corner, at least a quarter inch in from the top and left edges. Leave it off and mail that cannot be delivered goes to the Mail Recovery Center in Atlanta instead of coming back to you.

  • Postage

    Top right, 1.5 in square

    Top right corner. A stamp placed anywhere else can be missed by the canceling machine, which means the letter gets pulled out and handled by hand.

  • Delivery address

    Centered, inside the OCR read area

    This is the block the scanner reads. Keep it inside the middle band of the envelope, all in one font, with no punctuation and nothing else written near it.

  • Barcode clearance

    Bottom 0.625 in, right 4.75 in

    The bottom 5/8 inch across the right side of the envelope has to stay empty. The sorting machine prints a barcode here. A decorative border or a low line of writing can corrupt it.

The five steps

  1. Put your own address in the top left corner

    Your name, street, and city line, small, in the top left. This is the only thing that brings the letter back to you if delivery fails.

  2. Write the recipient name on the center first line

    The full name the person actually receives mail under. For businesses, the company name goes on its own line under the person.

  3. Write the street line, with any unit at the end

    Number, direction, street, then APT or STE and the unit. All one line, no commas.

    JORDAN REYES1420 N BROADWAY APT 4BDENVER CO 80202
    CorrectThe delivery line carries the whole location.

  4. Finish with city, state and ZIP on one line

    The two letter state code and the ZIP. The nine digit ZIP is better if you know it.

  5. Stamp in the top right, and leave the bottom strip empty

    The stamp goes in the top right corner. The bottom 5/8 inch stays clear across the right side, because the machine prints its barcode there.

The formatting rules that matter

These apply to every envelope, whatever the situation. They exist because of how the scanner reads, not because of manners.

RuleWhy
No commas or periods anywhere in the addressEvery stray mark is a chance for a misread
Two letter state codes, never spelled outCO is in the address file. Colorado is prose.
Unit numbers at the end of the street lineThe line above the city is the delivery line
Dark ink on a light envelopeThe scanner needs contrast to read anything at all
Bottom 5/8 inch left clearThe machine prints its own barcode there

Every situation, one page each

The five steps cover a plain letter. Real envelopes have doctors, widows, army bases and post office boxes on them. Each one has its own page with the exact lines written out.

Questions people ask

Does handwriting have to be in capital letters?
No. Neat mixed case is read fine. Capitals with no punctuation are what the Postal Service asks for because they read most reliably, so use them when a letter really matters.
Which pen should I use?
Black or dark blue ink on a light envelope. Pencil smudges, and light or metallic inks are the ones the scanner struggles with.
Where does the return address go, front or back flap?
Front top left. A return address on the back flap is common on invitations, but the scanner only photographs the front, so a front corner return is the one that actually works when delivery fails.
What if the address is one line too long for the envelope?
Move the unit to its own line above the street as a last resort, and never below it. The line right above the city is read as the delivery line.