How to Fit a Door

Four Parts:Preparing for InstallationTrimming the DoorPlacing your hingesHang the Door

Replacing a door in your home, such as a cheap hollow-core door, is a fairly simple process with the right tools and a little know-how. Nonetheless, doing it incorrectly can result in uneven gaps in the spaces around the door, or worse, a door that won't even latch. Following these instructions will help you to sidestep possible problems and hang your new door correctly and easily.

Part 1
Preparing for Installation

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    Remove the old door. Before anything else, the old door must be removed. Depending on your hinges and whether or not you want to reuse them, there are two possible approaches to this
    • If you don't want to reuse the old hinges, or if they don't have removable pins, you'll need to not only unscrews the door from the hinges, but also the hinges from the frame.
    • If you have hinges with removable pins and you want to reuse them, you can save yourself some steps later by just removing the pins that hold the hinges together. This will allow you to remove the door but leave one part of the hinges attached to the door frame. Start with the top hinge and work your way down. Then, take the door down and remove the hinge parts that are affixed to it.
    • If the pin won't come out easily, tap it gentle from below with a hammer and screwdriver.[1]
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    Measure the door opening. Using a measuring tape, measure the height and width of the inside edge of the door opening and saddle board.
    • If the doorway is in place where there is a transition between different types of flooring and the floor is of two different heights, measure the high side, as this may necessitate trimming the bottom of the door more.[2]
    • If the old door was a good fit, you may find it easier to measure the door itself.
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    Purchase a door. Find a door you like that is close in size to your opening. You will be trimming the door, so you don't need to worry about it being exactly the right size.

Part 2
Trimming the Door

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    Mark the door for trimming. Use a pencil to apply the measurements equally on both sides of the door so as not to take too much off one side. Repeat this process for the top and bottom.
    • Doing all the trimming on one side is is bad practice and may result in the door looking wider on one side than the other.
    • A good rule of thumb would be to allow a 2mm gap on the two sides and top and allow a gap of 8mm between the saddle board and the bottom of the door.[3]
    • If you think the door you bought is already a perfect fit, you can "dry fit" the door, standing it up in the space. It should fit as specified above, except that that the large gap will be at the top.
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    Trim the door. Score your pencil marks with a utility knife to prevent the wood from splintering. Then, use a circular saw and cut off the excess wood, using a straightedge to guide the saw.[4]
    • Placing tape over the cut line can also reduce splintering.[5]
    • If removing less than 3/16 of an inch, use a hand plane rather than a circular saw.
    • Bevel the edges of the door two to three degrees where it hits the stop so the door will clear the jamb smoothly.[6]
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    Check to see if the door fits. Place the door into the frame and see if it fits. Remember there should be a gap of 2mm (about the width of a nickel) around the sides and top and a gap of 8mm on the bottom.
    • An easy way to check the top and bottom is to sit the door on the floor. The gap at the top should now be 10mm (2mm top+8mm bottom). If the door does not meet these requirements the further planing is required.

Part 3
Placing your hinges

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    Mark the hinge positions on the frame. If using new hinges, check to see if they will fit in the spaces where the old hinges were. If they don't, rest them so the bottom lines up with the old hinge mortises (recesses), and mark the door frame along the top of the hinge.[7]
    • Then, chisel out the additional space to widen your hinge mortises.
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    Mark out your hinges on the door. The easiest way to do do this, if the old door was a good fit, is to lay the new door on top of the old door so the edges are flush. Then, line up a combination square with the old door's hinge mortises and transfer their locations to the new door, marking the edges with a utility knife.[8]
    • Remember that the barrel/pivot of the hinge is on the pull side of the door. If you are replacing an old door you should refit the hinges so they are facing the same way as the old one.
    • If the old door was not a good fit or is too different in size from the new door, place the new door in the frame and use shims around the edges to set it in place. Then, using the mortises in the frame, mark the door where the hinge mortises will need to be made in order to line up.[9]
    • The advantage of this method is that you can also mark the latch-hole at this point for easier installation of the doorknob.
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    Cut hinge mortises. Lay a protective pad on the floor and support the door on its side. Then carefully extract the surplus wood from the door until you have reached the required thickness.[10]
    • First, hold the chisel vertically and tap it with a hammer to outline the edges of the mortise. Then, make a series of closely spaced cuts that are about as deep as the thickness of the hinge. Finally, hold the chisel at a low angle with its beveled face flat against the wood and lightly tap the chisel with the hammer, chipping away the wood in small pieces.[11]
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    Create a mortise and holes for your lock and door handle. Create a mortise for the plate around the latch on your door using the technique described above. Then, use a drill to make the necessary holes for installation of your doorknob/door handle and lock.[12]
    • This process will vary somewhat based on the doorknob you are installing. Follow the instructions that came with your door handle.
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    Screw on the hinges. Set the hinge into the mortise and use and centering punch to make starting divots for the screws. Then, screw the hinges to the door and ensure the hinges and the screw heads are flush.[13]
    • If you are using hinges with removable pins, you can take the hinge apart and just attach one side to the door. In this case, attach the other side of the hinge to the door frame, and proceed to the next step. Otherwise, skip to step two of the next section.

Part 4
Hang the Door

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    Interlace the knuckles and replace the pins. If you are using hinges with removable pins and already have half of the hinge affixed to the door frame, interlace the knuckles of the two sides of each of the hinges and put the pins back in place once they are aligned.[14]
    • This will be much easier if you have assistant who can replace the pins.
    • Check to see if the door is swinging smoothly. If so, proceed to the final step.
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    Screw the door onto the frame. If your hinges don't come apart, your next step will be to support the door at a right angle to the frame. Place shims beneath it so that it reaches the proper height for the hinges to line up with the frame mortises.[15]
    • If the holes on the new hinge line up with the holes that were used to mount the old door, you can just screw the hinges to the frame. If not, you'll need to make divots in the frame with a center punch.
    • It's a good idea to start by only driving in one screw per hinge. Then you can check to see if the door swings easily. If so, drive in the other screws. If not, remove the screws and adjust the position of the hinges as necessary.[16]
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    Fit the lock and handles. If your door is swinging easily, it is now time to install your doorknob/handle and lock. This process will vary depending on the door handle you've chosen. Refer to the instructions that came with your doorknob.


  • If you are painting your door, do so before installing the hinges and door handle to keep these parts free of paint.[17]
  • A good way to hold a door upright on its edge is to put "feet" on it by screwing long, wide scraps of wood to the top and bottom ends, resting them tight against the floor. Take them off when you're done creating your mortises. No one will ever see the holes![18]


  • Always wear a dust mask and safety goggles while drilling, sawing, or chiseling wood. Obey all power tool safety instructions.

Article Info

Categories: Doors and Windows