The first thing you see when looking for a house is the mailbox; therefore, I decided to update it by creating a DIY mailbox to increase the curb appeal.
I chose the same type of wood as our other outdoor structures (trellis, lanterns, obelisk, wooden shutters, and flower box).
If you have been following my blog, then you know I am obsessed with solar lights, so I had to add one to this DIY modern mailbox.

DIY Mailbox
This post contains affiliate links. In other words, if you purchase from one of these links, I will make a small commission, but rest assured, you will not pay more for any products.
How to Build a DIY Mailbox
The first thing I had to do was to find out the requirements for the mailbox height and the best placement from the road. You can find the US Post Office requirements on their website.

DIY Wooden Mailbox supplies
Mailbox Building Supplies
4x4x8 pressure treated 2 each
1x6x8 pressure treated 6 each
2x8x20 inches pressure treated
Concrete two 40 lb bag
5-inch screws, 2 each
4-inch deck screws (4 each)
2-inch galvanized finish nails
1-inch stainless steel screws (4 each)
Mailbox 7x8x20
Tools
Post hole digger
Shovel
Level
Speed square
Measuring tape
Speed Horses
DIY Mailbox Posts

Measure and mark posts

Short boards on the back post
Building the Mailbox Sides
Next, cut fourteen 1x6x25 inch and four 1x6x7 inch pressure-treated boards.
Then, attach the 1x6x7″ boards to the upper portion of the back post with 2-inch galvanized finish nails.
You will want to use a speed square to keep the sideboard square to posts.
Next, place the posts parallel to each other, keeping them 25 inches apart (outside measurement).
Then attach the side boards to the front and back posts starting below the 7″ boards using with 2-inch galvanized finish nails.

Side view of the long boards on posts
Please note: this view is of the first side of the wooden mailbox holder. Once you finish this side, you will repeat the process on the other side.

Top view of posts and the first side of the mailbox
Next, we marked the trim for the inside of the back post. Note: we will attach it later.

Marking the trim piece
Next, turn over the wooden mailbox assembly and repeat the same process as the other side.

The unfinished side of the mailbox assembly
Wooden Mailbox Trim – Sides
To create finished edges, we used 1×6 pressure-treated lumber.
First, we measured the assembly to get the exact sizes for our side trim cuts.
Note: lumber varies in size.
These are the side trim cuts we used: long front 1x6x38.5, short front 1x7x6, and back 1x6x49.5
However, these measurements could vary, so you must measure your wooden assembly for the exact measurements.
Next, attach the side trims with 2-inch galvanized nails.

Attaching front trim board
Top Trim
We added the top trim last since we wanted it to extend to cover the side trim boards.
Therefore, you will want to include the installed side trim in your measurements for the top trim boards.

Attach the long top trim board
Mailbox Mount
Next, we created a mailbox mount (AKA shelf) with a 2×8.
First, we measured the width and length of the metal mailbox then we cut the board to size.
Then, we mitered the front edge of the mount board at a 60-degree angle to allow the mailbox to open.

Mailbox mount

Mitered mailbox mounting board
Tip:
At this point, you will want to check the fit of your metal mailbox on the “shelf” of your wood mailbox holder.

Check metal box fit
Note: We installed the metal mailbox onto the mounted board using 1-inch stainless steel screws through the holes in the bottom lip of the mailbox. We did this after it was installed in the ground.
DIY Mailbox Install
To install the mailbox, we dug two holes 16 inches deep and 25 inches apart.
Then we placed the box posts into the holes. We backfilled the holes and then checked them for level.
Once it was level, we added the dry cement and water as we went. Next, we packed the cement around the posts and sloped it away from the wood.

Measure the holes for install

Place wood assembly into holes.

Use a level to check that the installation is plumb.

Use concrete to secure posts.

Attach the metal box to the DIY wood mailbox assembly
Mailbox House Numbers and Solar Light
Supplies:
Since I am obsessed with solar lights, I decided to use one to illuminate the house numbers.

House numbers and tools for installation

Measure and mark the side of the DIY Mailbox for installing the solar light

Attach house numbers

Night view of the DIY Modern Mailbox
See you soon,
Kippi
Ps. This post has been shared on Between Naps on the Porch.
Jason
Monday 14th of April 2025
I made this this weekend and it was very easy with the help of your plans. It only took me about 6 hours to complete once I had all of the material and tools gathered. Thank you!
Mike
Tuesday 8th of April 2025
I saw that you cut your side pieces at 25 inches. Wouldn't it make more sense to do 24 inches so you can get 4 boards out of each 8 foot section of 1x6?
James
Sunday 1st of September 2024
Did you put a finish stain on sides?
Brittany
Saturday 3rd of August 2024
Where do you use the 5” screws?
Wednesday 5th of March 2025
@Brittany, to connect the 4x4s together at the top of the back post.
Michael Wright
Sunday 30th of June 2024
I’m getting ready to build this mailbox. I was just wondering where did you use the 4 inch deck screws I think I have everything else figured out Great Tutorial.
Wednesday 5th of March 2025
@Michael Wright, used to connect the 4x4s together at the top of the back post.
Saturday 23rd of November 2024
@Michael Wright, probably securing the 2x8 mount to the stand