To mail an envelope with USPS, address it clearly, confirm that its size, shape and weight fit the intended mail class, attach enough postage in the upper-right corner, seal it, and place it in an appropriate mailbox, collection box or Post Office acceptance point.

1. Choose and prepare the envelope

Use an envelope large enough to hold the contents without rigid bulges, clasps or loose objects. Standard letter pricing depends on more than weight: dimensions, thickness, flexibility and aspect ratio can make a piece nonmachinable or move it to another mail category.

2. Write the addresses

Put the recipient’s name and delivery address in the center. Put the return address in the upper-left corner. Use dark ink, complete city, state and ZIP Code information, and leave the lower-right area clear for postal processing.

3. Calculate and attach postage

Weigh the sealed envelope, not the loose contents. As of July 12, 2026, a stamped one-ounce First-Class Mail letter costs $0.82; additional weight and nonmachinable characteristics cost more. Place stamps in the upper-right corner without overlapping them.

4. Deposit the mail

A properly prepared ordinary letter can go in your outgoing residential mailbox, an eligible USPS blue collection box, or a Post Office. Use a staffed counter when the piece is unusual, you need a receipt or tracking, or you are unsure about classification.

Final checklist

  • Envelope sealed and contents secure
  • Delivery and return addresses complete
  • Size, shape and weight checked
  • Enough postage attached
  • Appropriate deposit point selected

Related guides and products

Sources and verification

Checked September 4, 2026. Postal prices and availability can change.

Explore this topic

Preview each focused page below to understand its core task before opening it. The topic center provides the overview; each child page handles its own detailed answer.

Primary sources