Mailbox Installation

How to Set Up & Mount a Mailbox

Follow U.S. Postal Service® guidelines for installing and placing a new mailbox at your home. Get tips on the best materials to use to set up a curbside mailbox and how to keep it in good condition. Make sure that your mail carrier always has a clear path to your mailbox whether it's by the street or mounted on your house.

Curbside Mailboxes

Mailbox Size & Construction Standards

A mailbox with the Postmaster General's (PMG) seal of approval meets USPS size and construction standards. If you build your own mailbox or buy a custom-made one, it must meet the PMG standards. Show your local postmaster your mailbox plans or your custom-made box for approval.

To get drawings and measurements for building your own mailbox, write to US Postal Service Engineering.

Want to buy a mailbox big enough for packages? See Next Generation Mailboxes.

Where to Place the Mailbox

Here are some helpful guidelines to follow when placing your mailbox:

  • Position your mailbox 41″ to 45″ from the road surface to the bottom of the mailbox or point of mail entry.
  • Place your mailbox 6″ to 8″ back from the curb. If you do not have a raised curb, contact your local postmaster for guidance.
  • Put your house or apartment number on the mailbox.
  • If your mailbox is on a different street from your house or apartment, put your full street address on the box.
Mailbox installation requirements. Place the mailbox 6 to 8 inches in from the curb. Dig the post hole so you can bury the mailbox post with 41 to 45 inches of mailbox post showing above the ground. Touch or click to open modal.

Installing the Mailbox Post

The best mailbox supports are stable but bend or fall away if a car hits them. The Federal Highway Administration recommends:

  • A 4″ x 4″ wooden support or a 2″-diameter standard steel or aluminum pipe.
  • Avoid unyielding and potentially dangerous supports, like heavy metal pipes, concrete posts, and farm equipment (e.g., milk cans filled with concrete).
  • Bury your post no more than 24″ deep.

Door Slots & Wall Mailboxes

Approved Door Slots

Some homes and apartments have a slot in the door for receiving mail instead of a mailbox. The standards for an approved door slot are:

  • The opening must be at least 1 1/2″ x 7″.
  • The bottom of the slot must be at least 30″ above floor.
  • Horizontal slots must have a flap hinged at the top.
  • Vertical slots must be hinged on the opposite side from the door's hinges.

For greater privacy, you can also install a mail slot hood on the inside of your door to prevent someone from seeing into your home. The standards for door slot hoods are:

  • The hood should not project more than 2 1/16″ beyond the inside of the door.
  • On a horizontal slot, the hood should not extend below the bottom of the outside plate.
  • On a vertical slot, the hood should not extend beyond the side of the outside plate on same side as the door's hinges.

Wall-Mounted Mailboxes

  • To replace your curbside mailbox with a wall-mounted mailbox, you must get your local postmaster's permission.
  • Choose from a variety of mailbox sizes and styles; mounted mailboxes are not required to have a PMG seal of approval.
  • Get a wall mailbox that can hold a normal day's mail volume, including letter-sized envelopes, postcards, and catalogs.*
  • Place the mailbox near the main entrance so your mail carrier can easily see it.

*Note: Wall-mounted mailboxes may only be used for items with postage. Newspapers may not be placed in the mailbox.


Mailboxes take a beating from the weather, so we recommend an annual mailbox checkup to avoid damage to your mail or difficulty identifying your address.

  • Tighten loose hinges on the door
  • Take care of rusty or loose parts
  • Replace missing or faded house numbers
  • Keep the path to your mailbox clear