How to Trim the Bottom of a Door

New carpeting and flooring are just two home improvements that can require the trimming of an interior or exterior door.
Following the procedure used by professional carpenters will ensure a clean and accurate cut.

Step 1

Close the door to be trimmed and mark the cut height above the floor. Set the mark at ?-inch above the plane of the floor surface the door must clear. If the door is not hung in the doorway, use a builder's level across the adjacent floor surface within the door’s swing radius, then measure from the bottom of the level to the bottom of the lowest hinge.

Step 2

Remove the door from the door jamb, if applicable. Use a hammer and nailset to tap the hinge pins up from the bottom and remove the pins to remove the door.

Step 3

Rest the door horizontally across sawhorses and measure the dimension from the top of the door to the cut line marked in Step 1. If the level method was used to determine the floor line, measure the dimension down from the lowest hinge minus ?-inch and mark a line.

Step 4

Transfer the measurement determined in Step 3 to the opposite door edge. Use a builders level as a straight edge and draw a pencil line to connect the two marks. This is the cut line. Use a hand square to mark the cut line across both door edges.

Step 5

Score the cut line with a utility knife. A framing square makes an excellent straight edged guide for the knife cut. Score to a minimum of 1/8-inch deep. Score both edge lines in the same way.

Step 6

Retract the blade guard on the circular saw and measure the dimension between the edge of the saw table and the face of the saw blade. Either side can be measured and will determine the positioning of the saw guide set in Step 8.

Step 7

Mark the distance determined in Step 6, minus 1/16-inch, above the door’s cut line at both door edges.

Step 8

Lay a builder's level flat on the door’s surface, connecting the two lines measured in Step 7, positioning the level on the upper side of the line. Clamp the level securely in place.

Step 9

Use the level secured in Step 8 as a saw guide, keeping the saw table edge measured in Step 6 against the level through the cutting of the door. Verify the blade alignment with the cut line prior to beginning the cut, keeping in mind the offset added in Step 7.

Step 10

Lightly sand any rough edges with medium sandpaper.

Step 11

Reposition the door in the opening by aligning the hinges and replacing the pins to each hinge.

Things You Will Need

  • Hammer
  • Nailset
  • Sawhorses
  • Tape measure
  • Utility knife
  • Framing square
  • Hand square
  • Builder's level
  • 2 clamps
  • Circular saw
  • Sandpaper


  • To help prevent chipping or splintering of the wood veneer door surface by the upward spin of the saw blade during the cutting, offset the saw guide about 1/16-inch from the cutting line.

About the Author

Paul Massey has been writing since 2009, drawing on a 35-year career in the construction industry. His experience includes 15 years as a general building contractor specializing in architectural design, custom homes, commercial development and historic renovations.