Do Mailboxes Have To Be A Certain Height? (Basic Rules)

Since the United States Postal Service delivers mail to more than 163 million addresses all over the country, it makes sense that they would want some standardization for the size of mailboxes.

If you’re looking to buy a new mailbox or install a custom mailbox, you’ll need to follow some guidelines to ensure your mail is properly delivered.

Mailboxes Have to Meet the Requirements Set by the USPS: 

Your mailbox must be on a secure stand between 41 and 45 inches above the road’s surface. The measurement is from the bottom of the box, where the door opens. The opening of the mailbox must be between six to eight inches from the road.

What Height is the Average Mailbox?

Below, we’ll look at the height requirements for mailboxes placed near the curb which have mail delivered by a postal worker in a postal vehicle. We’ll explore options for other types of mailboxes below.

The average mailbox meets the USPS requirements of standing on a post between 41 and 45 inches high. The opening of the mailbox needs to be set between six and eight inches back from the curb, and the mailbox post should be buried 24 inches into the ground. 

Since most mailboxes are between 10 to 12 inches tall at their tallest point, the total height will be anywhere between 51 to 57 inches at the top of the mailbox.

The USPS advises that you choose a mounting post that is sturdy enough to resist the elements but will give way to an oncoming car. Common materials are wooden 4″ x 4″ posts or hollow metal posts.

Things like concrete-filled posts or stone pillars are generally not recommended.

Approved Mailboxes

If you’re not looking to build a custom mailbox, you can get one from a big box hardware store or purchase one from the internet.

However, before purchasing, ensure that the mailbox has the seal “Approved by the Postmaster General.”

You’re not wasting money on a mailbox you can’t use, and you’ll still get your mail delivered.

Stores that sell mailboxes also usually sell posts, and the employees can advise you on the best ways to secure your new mailbox.

Can Mailboxes be Too Tall?

Yes. If you put your mailbox on a post higher than 45 inches, your mailbox will be too tall.

It’s important to measure the length of the post, not including the height of the mailbox itself. 

However, if you want to position your mailbox at the upper limit, you’ll need a more than 45 inches post since you’ll need to bury the post in the ground to secure the mailbox. 

Also, keep in mind that the measurement is from the road to the bottom of the mailbox, so if you’re placing your mailbox on a sloping surface, make sure it doesn’t exceed 45 inches.

Can Mailboxes be Too Short?

Absolutely! The lowest height that the United States Postal Service will accept is 41 inches from the bottom of the mailbox to the ground. 

If you want to be as low profile as possible, get a post long enough to bury the post securely in the ground and measure 41 inches from the ground. Secure the mailbox on top, and you’re all done. 

Can My Custom Mailbox be Any Height?

There are requirements for the height of the mailbox post, but there are also requirements for the actual size of custom-made mailboxes.

You’ll need to submit your plans to the Office of the Postmaster General to get approval for your design. 

Who is the Postmaster General? 

The person who holds this fancy title is the United States Postal Service CEO.

They manage and direct the agency, and they’re appointed by the Board of Governors of the Postal Service.

The President of the United States appoints the board members. 

So My Mailbox Plans Have to Go To Washington DC? 

Some local postmasters can approve your mailbox according to the requirements set by the Postmaster General.

The USPS website has a tool where you can find the right person to contact about your mailbox. 

What is the Ideal Mailbox Shape and Height?

The most common mailbox shape is rectangular with a curved top on the bottom.

They’re generally almost 9 inches wide and just over 11 inches tall. They have an interior depth of 21 & 1/4 inches. 

The mail opening will be slightly smaller since the door will need clearance. However, these dimensions are usually suitable for the regular mail that a person will receive. 

If you frequently get packages that come in soft envelopes or small boxes, it may be worth investing in a slightly larger mailbox so that your mail delivery person can easily put these items in the box. 

These are known as “next generation” mailboxes, and they’re 13.63 inches wide, 7.75 inches tall on the sides, 12 inches tall at the center, and 16.5 inches deep. They’re designed by the USPS and will fit onto most standard posts. 

Additional Mailbox Types 

In some areas of the country, other mailbox styles are used. These include wall-mounted or door slot mailboxes and mailbox clusters. 

If you live in a neighborhood with a mailbox cluster, you won’t need to do anything specific. The USPS installs these to their requirements. 

If a person on foot delivers your mail, you may choose a mail slot in your door or a wall-mounted mailbox. 

The door slots must be at least 7 inches across by 1 & 1/2 inches tall. The bottom of the slot must be at least 30 inches from the bottom of the door, and they must have a hinged door to allow the mail through. 

If you choose to have the wall-mounted box, you have a lot more freedom on the size and style of your mailbox since they don’t have to be approved by the Postmaster General. The only requirement is that it be easily accessible to the mail carrier and big enough to hold a normal volume of mail. 


Mailbox Installation | USPS