How To Miter Cut Molding

Moldings feature in three main areas of the home:

    • ceiling moldings that conceal the gap between the ceiling and the wall
    • door and window moldings that trim gaps between windows, doors and surrounding walls, and
    base moldings that conceal gaps between floors and walls.

Because molding is most commonly joined at 90º angles, it stands to reason that most joints will be cut at 45º. Miter cutting molding is the simplest and most efficient way to cut moldings and join them at corners so that it all appears seamless. What mitering effectively means is to cut two pieces of wood at an angle that is equal to half of that of the corner angle.

Learning how to miter cut molding is a fairly basic skill that a home carpentry handy person will pick up early on in their DIY experiences. What’s needed is a miter box which helps to cut at exactly the correct angle by lining up the piece of molding and cutting via a slot in the box. Here’s how:

    1. Set your miter box at the appropriate angle. If you haven’t already read the instructions for the box, take this opportunity to do so to help you better understand. Note that the most basic miter boxes will only offer 45º or 90º cutting angles.
    2. When cutting chair rail or baseboard moldings, position the moldings in the box just as you would on the wall, resting the flat side along the back of the miter box. For standard window or corner door casings, place the molding face up at the bottom of the box.
    3. Using a hand or power miter saw, but the wood at your 45º angle.

How to miter cut crown molding

Position the molding upside down and face up in your miter box so that the ceiling side of the molding rests flat against the bottom.

Inside corners:

    1. After measuring the piece of molding from corner to corner, pencil in the cuts on the back.
    2. Place it upside down in the box, resting the flat part flush against the back and bottom of the box. Use caution when cutting because with the molding upside down, the stability is compromised.
    3. Set your saw to 45º and cut.

Outside corners:

    1. Again measure the molding from one corner to the other and pencil in the cuts on the back.
    2. Place the molding in the box upside down and at an identical angle to what it will be on the wall or ceiling.
    3. Cut at 45º. The left hand corner will be on the left of the blade of the saw while the right hand corner will be on the right.

How to miter cut molding the easiest way

Miter boxes are excellent tools for home handy people, especially if the need is only for basic cuts. However, if you really want to ensure a precise fit and tidy appearance, you could invest in a table saw or power saw.

Table saws feature miter gauges and a range of angles indicated on them. You can actually set the angle to 45º and lock it in place to make miter cutting very simple. Still, even though miter boxes could be considered rudimentary by comparison, they teach you accuracy and attention to detail and should never be undervalued.

Our Most Popular Online Tips