How to Install Mail Slots in Doors

Many people who must be away from their home all day face very real security risks, such as identity theft, when their mail must sit in an easy to access mailbox throughout the day. This is one reason to consider installing a mail slot, or letter slot as it is sometimes called, on your door. A mail slot is also ideal for the elderly and those with limited mobility, especially in inclement weather. Available in a multitude of finishes, such as cast iron, stainless steel, brass, antique brass or aluminum, there is sure to be one to complement your d�cor. Installing a letter slot in your door is a relatively easy job that, with a few household tools, can be finished in 2 hours or less.


  1. 1
    Purchase your mail slot. Buy the largest one that will fit on your door to accommodate larger envelopes and magazines. Another good idea is buying one with a basket to catch the mail as it comes through the door slot rather than allowing it to scatter across your entryway.
  2. 2
    Stand in front of your door and determine the best height in which to install the mail slot. Make a pencil mark at that height to use when you begin laying out the template.
  3. 3
    Remove the door from its hinges and lay across 2 sawhorses, making sure the side that has the pencil mark denoting the height is facing up. While not strictly necessary, installation is much easier if your door is on a flat surface.
  4. 4
    Lay the template on the door, lining it up with your pencil mark. Trace the rectangular outline of the mail slot onto the door.
  5. 5
    Put on protective eye gear and a face mask if desired.
  6. 6
    Drill a hole large enough to allow the jigsaw to pass through at each corner of the outline, and then cut the hole with the jigsaw, sanding any rough edges.
  7. 7
    Mark the holes for the bolts used to mount the hardware, and drill the holes with a twist drill bit the same size as the bolts. Line up the front of the mail slot with your holes and attach it with the bolts from the mounting kit. Use pliers or a wrench to ensure the bolts are firmly embedded in the lug nuts. You may have to trim some excess length from the bolts using a hacksaw depending on the thickness of your door.
  8. 8
    Attach the interior frame as directed in your installation kit.
  9. 9
    Rehang door.


  • Buy after market insulation kits for your mail slot to reduce heat and air conditioning loss if your letter slot kit does not have one. You can also buy a can of foam insulation and spray it into the door slot before attaching the inside trim.
  • Purchase vertical mail slots, much like the lock boxes in apartment house lobbies, to fit doors with large windows or decorative accents that you wish to preserve.


  • The post office bans mail carriers delivering mail to your door if they have to walk across ice or snow to reach it, so be sure to keep your entrance clear.
  • Check with your local post office to make sure the mail carriers will deliver to the door. Many jurisdictions do not allow them, even in older neighborhoods where they were once the only way to receive mail.

Things You'll Need

  • Mail slot kit
  • Pencil
  • Sawhorses
  • Drill
  • Standard drill bit
  • Twist drill bit
  • Jigsaw
  • Sandpaper
  • Screwdriver
  • Wrench or pliers
  • Eye protection
  • Dust mask
  • Hacksaw (if needed)
  • Spray foam insulation (if needed)

Article Info

Categories: Doors and Windows