How to Install a Mailbox

Learning how to install a mailbox post and the associated box doesn’t mean calling in the professionals. Here’s the step-by-step to help you get the job done.

USPS requirements state that a mailbox can be no taller than 45 inches above street level. Since most streets have a curb, the standard mailbox height is 42 inches above ground level. So, the total height is around 45 inches; 42 inches from the ground, plus the few inches added by the curb.

• Measure the height of your mailbox post. USPS requirements state that a mailbox height must be 41 to 45 inches above the road's surface. Standard mailbox height above the ground is 42 inches.
• Mark a spot on your lawn six to eight inches back from your curb. If you do not have a raised curb, contact your local postmaster for guidance.
• Use a post hole digger to dig a hole for your post at this spot. Dig deep enough that the height of your mailbox above the ground is around 42 inches. Do not dig deeper than 24 inches.
• Put a shovel full of gravel in the bottom of the hole.

Make sure your desired mailbox post meets Federal Highway administration recommendations: stable mailbox posts that can bend or fall to the side if hit by a car. Avoid unyielding supports such as large-diameter metal or concrete posts, and instead use a 4 x 4-inch wooden support or a 2-inch diameter standard steel or aluminum pipe.

• Insert the mailbox post into the hole.
• Measure the height of the mailbox above the ground to ensure it’s around 42 inches.
• Do not bury your post deeper than 24 inches. Cut the post if necessary.
• If the hole is too deep, add more gravel to bring the post up.
• Use a post level to ensure the mailbox post is straight.
• If your chosen mailbox post comes with manufacturer's instructions, double-check that you are following those closely while you work through this guide's steps.
• Drive a wooden stake into the ground on one side of the post, about 2 feet away.
• Span the distance between the post and stake with a piece of lumber. Fasten it to the post with one screw.
• Straighten the post in that direction, then fasten the board to the stake with two screws and drive another screw into the post.
• Move 90 degrees around the post and repeat the process with another stake and support.
• If needed, two more stakes and supports can be added.

While installing a mailbox without concrete may be possible, long-term installations fare better with the security that concrete can provide. Here’s how to pour concrete to keep post-mount mailboxes in place for the long haul:

• Prepare a bag of fast-setting concrete mix per manufacturer’s instructions and pour into the hole, around the post.
• Allow a few inches of space at the top of the hole – do not fill the concrete flush with the ground’s surface.
• Immediately after pouring, check the post level to double-check your mailbox. If it has shifted slightly uneven, adjust now before the concrete begins to cure.

Tip: A 50-pound bag of concrete should suffice for this project.

• Allow the concrete to cure. The length of time this will take depends upon the type of concrete you used – check the concrete label for specifics.
• Leave the support beams around the mailbox until you are certain the concrete is completely set.

• Make sure you follow any specific instructions provided by the manufacturer when figuring out how to attach a mailbox to a post.

• USPS requires that each mailbox be clearly labeled with its corresponding house numbers and address letters.
• Add your street address or house number on the side of the mailbox with numbers at least one inch tall.
• Per USPS guidelines, if your mailbox is on a different street than your home, put your full street address on the mailbox.

Tip: If you are constructing your own mailbox, contact your local postmaster to go over the mailbox plans and confirm the design follows USPS standards.

• There may be a few inches of empty space in the post hole above the concrete. You can fill this in with soil to bring it level with the surrounding ground.
• Improve your curb appeal by turning your mailbox area into a small garden in your front yard.
• Regularly inspect your mailbox to ensure it is holding up well against the weather and normal wear and tear. Once a year, check for loose hinges and rust. If you notice something has obstructed a clear path to the mailbox or that the house numbers have become lost or faded, fix the problem immediately.

In some cases, it will be necessary to mount a mailbox directly to a wall rather than installing it as a free-standing structure.

• Hold the mailbox against the wall at its desired installation location.
• Double-check that this location is easily accessible from your sidewalk, front steps or porch so that the mail deliverer will not have any trouble finding it.
• Use a level to ensure you're holding the mailbox flat.
• Open the mailbox and insert a pencil through the mounting holes on the back of the mailbox to mark the wall.

Tip: Some wall-mount mailboxes come with an installation template that allow you to affix a sheet of paper or cardboard to the wall for easier marking.

• Drill into the wall at each of the points you just marked.
• You don’t need to drill very deep for this installation. Typically, you can use a 1/4-inch drill bit for brick or masonry walls and a 1/16-inch drill bit for wood walls.
• Check the installation instructions that came with your mailbox to double-check the requirements for your individual unit.

• For masonry or brick walls, insert plastic anchors into each drilled hole and tap lightly if necessary.
• Attach any mailbox hardware necessary to your box or the wall as instructed on your provided installation manual.

Tip: Often, installation hardware is not included with your wall-mounted mailbox. Check the mailbox’s manual for specifics on what you need to purchase additionally for proper installation.

• Insert screws into the top holes and hang on the wall, only twisting the screws in halfway.
• Rest a level on top of the mailbox to double-check it is flat. Adjust if necessary.
• Insert screws into the bottom holes and drill in only halfway, again checking that mailbox is level.
• Once you’re certain the mailbox is level, drill all screws in securely.