How to Replace an Interior Door

A pair of hands installing a doorknob on a door.
  • 2-4 hours
  • Beginner
  • 200-400
What You'll Need
Measuring tape
Circular saw
Straight edge
Hand plane
Utility knife
Combination Square
Paint / wood stain

Updating interior doors can transform the look of your home. While replacing interior doors sounds easy enough, improperly installing the new door can leave uneven gaps along the floor or jamb. Fortunately, there is an easy way to replace interior doors without too much time or fuss.

Step 1 - Check the Measurements

Before you start removing the old door, you’ll want to make sure that everything fits properly. Measure and record the height and width of the door and bring these measurements with you when you purchase the new door. Doors typically come at 80 inches in height, but vary greatly on width.

Step 2 - Remove the Pins

Use a hammer and screwdriver to remove the pins that keep the hinges in place. Start with the bottom hinge and go up to prevent the door from falling on you. If the pins aren’t loose enough to wiggle free by hand, use a hammer to gently tap the pins free. You can keep the pins in the jamb hinge to prevent losing them.

Step 3 - Align Both Doors

Unscrew the old hinges and the lockset, taking notes on their position if you plan on reusing them. Lay the old door on top of the new door and align them flush. The old door will serve as a template for the new door. Simply trace around the old door using a pencil. The lines will tell you areas that need trimming.

Step 4 - Trim the New Door Down

If the new door doesn’t perfectly align with the old one, then you’ll need to trim it down to size. Use a utility knife to score the pencil marks. This will help prevent splintering during the cutting process. Trim the new door using a circular saw and straight edge. If you need to trim less than a quarter inch, then a hand plane is better equipped for the job.

Step 5 - Cut Out Hinge Slots

For blank doors, you’ll need to cut out slots for the hinges. To accomplish this, align the old and new doors with each other. With all four sides flush, mark out the hinge locations on the new door with a combination square. You can use a utility knife to make the marks and pay close attention to the gap between the hinge and the outer part of the door.

Step 6 - Chisel the Mortise

Chiseling out a hinge mortise is the most difficult part of this project. Place the chisel perpendicular to the markings and hammer out the outline of the hinge, being careful not to go too deep. Then, cut a series of grooves inside the hinge. These cuts will make the removal process easier. Next, hammer the chisel at a low angle and start removing the unwanted material. Work slowly and use constant pressure to keep the chisel from slipping.

Step 7 - Screw the Hinges In

Use the hinge to check for proper depth of the mortise. Once the depth has been reached, it’s time to screw the hinges in place. If you accidentally go too deep with the chisel, a thin shim can be used to bridge the gap. It’s also recommended to drill pilot holes into the door before screwing the hinges in place.

Step 8 - Use Shims to Adjust

Test the new door by making sure all the hinges line up and the lockset lines up with the latch. Adjust wherever necessary using shims. Once everything lines up, mark the exact location where the edge of the door meets the strike plate.

Step 9 - Get the Lockset Measurements

You can use the old door for the lockset measurements, but only if you are using the previous hardware. If you bought a new lockset, use the template as a guide for proper installation.

Step 10 - Paint or Stain the Door

Before you install the new door, take some time to paint or stain it. Do this before you install the lockset. Once the paint is dry, insert the new lockset in place and get ready to hang the door.

Step 11 - Hang the New Door

Hanging the new door is best done with a helper. Hold the door so that the hinge knuckles interlock with each other. After they are in place, use your helper to install the pins. With all the pins in place, test the door for smooth operation and adjust wherever necessary.