Sending Mail

Preparing Domestic Mail

Send domestic mail easily with USPS®. Properly preparing your letters and postcards will get them where they’re going on time and save you money.

For how to ship a package, see Sending Packages.

For mail and packages sent from and to the U.S., see Preparing International Shipments.

How to Send a Letter or Postcard

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Step 1: Choose Envelope or Postcard

When mailing a letter or postcard, postage cost depends on the size and shape of the mailpiece. You can save money mailing standard sizes that fit through automated mail-processing equipment.

Size & Weight Determine Price

All envelopes must be flat. If your envelope can’t fit through automated processing equipment it is considered nonmachinable and costs more to send. Nonmachinable items include lumpy or rigid envelopes, and those that have clasps, string, or buttons. Unusually shaped square or vertical envelopes will also cost more to send.


  • Envelopes must be made of paper.
  • Envelopes must be rectangular to qualify for letter prices.
  • Envelopes larger than letter-size will be charged package prices.
  • Large envelopes must be rectangular to qualify for Flat Rate prices.


  • Postcards must be rectangular to qualify for First-Class Mail® prices.
  • Oversized postcards will be charged letter or large envelope prices.
Size & Weight Requirements – Postcards & Envelopes

Step 2: Address Your Mail

Write or print your return address and the address you're mailing to clearly in the correct spots to make sure your mail is delivered on time.

Address Format

Envelopes with addresses that are unclear or written in the wrong place may not get delivered.

  • Print addresses neatly in capital letters.
  • Use a pen or permanent marker.
  • Do not use commas or periods.
  • Include the ZIP+4® Code whenever possible.

Write Recipient Address

Write the recipient’s address in the bottom center of the envelope. Include the following on separate lines:

  • Recipient's full name or company name
  • Full street address and apartment or suite number, if applicable
  • City, State, and ZIP+4 Code

If the apartment or suite number cannot fit on the delivery address line above the city, state, and ZIP+4 Code, place it on a separate line immediately above the delivery address line.

  • Recipient's full name or company name
  • Apartment or suite number
  • Full street address
  • City, State, and ZIP+4 Code
Secondary Address Unit Examples

Write Sender Address

Write the sender’s address in the top-left corner. Include the following on separate lines:

  • Sender’s full name or company name
  • Full street address and apartment or suite number, if applicable
  • City, State, and ZIP+4 Code
Postal Addressing Standards

Special U.S. Addresses

Puerto Rico

Mail to Puerto Rico, the U.S. Virgin Islands, or an APO/FPO/DPO has specific address requirements.

Most Puerto Rico addresses have the same format as standard addresses. Others include an urbanization or community code for a specific area or development. Addresses with an urbanization code, abbreviated URB, should be written on four lines.

SAN JUAN PR 00926-3232

Puerto Rico Address Examples
U.S. Virgin Islands

Virgin Islands addresses have the same format as normal addresses. The right abbreviation for this territory is “VI,” not “US VI” or “USA VI.”

RR 1 BOX 6601
KINGSHILL VI 00850-9802


To prevent mail from entering foreign mail networks, do not include city or country names in APO/FPO/DPO shipping addresses. Make sure you include the unit and box numbers, for APO/FPO/DPO shipping addresses (if assigned).

Military Address Examples

Step 3: Calculate & Apply Postage

How many stamps you need to mail your letter depends on where it's going, its size, and its weight. Requesting a Certified Mail Receipt or other proof of delivery will add to the price. The current price of a First-Class Mail® Forever® letter stamp is $0.58 and $0.40 for a postcard.

Paying for Postage

There are several things to consider when calculating a postage price.

  • Destination
  • Speed
  • Shape and size
  • Special handling and insurance
  • Delivery confirmation receipts

Calculate a Price

Insurance & Extra Services

Postage Options

There are several ways to get postage for your envelope.

  • The Postal Store®
    Shop online for all stamps and ad-on postage for oversized envelopes.
  • Click-N-Ship®
    Print and pay for your own postage for Priority Mail® and Priority Mail Express® envelopes.
  • Post Office Locations
    Buy stamps at Post Offices or at Approved Postal Providers® such as grocery and drug stores.

Step 4: Send Your Mail

Mailing your stamped envelope or postcard is easy. You can leave it for your mail carrier to pick up or drop it off in several locations.

To send your letter or postcard:

  • Leave it in your mailbox for carrier pickup.
  • Drop it off in a blue collection box.
  • Take it to a Post Office lobby drop.
Post Offices & Drop-Off Locations