How to Measure for Window Trim

Measuring for window trim is necessary to finish a window frame. The trim is the decorative area around the window that encloses the wood used to frame it in. It can vary in width and be either very ornamental or modest in design. Cutting window trim requires an electric miter saw or hand-held saw and a miter box. The measurements must be precise so the trim fits evenly together.

Measuring for Window Trim

The 4 pieces of wood that will comprise the window trim will each be trapezoidal in shape. At either end they will have 45 degree angled cuts facing inward, looking like a horizontal cross section of a triangle. The window frame represents the inside corners of the window trim. The trim meets in 4 places around the window on the inside edge and also in 4 places on the outside edge. To make accurate 45 degree angle cuts, measure from inside edge to inside edge of each piece. If the inside edges match up and the correct angled cuts are made, the outside corners will align as well.

Determine the 4 points around the window frame where the 4 pieces of trim will meet and measure from corner to corner. If accurately measured and cut, the 4 pieces of trim will join to create a perfect square or rectangle with flush edges between them.