How to Cut Baseboard Molding Using a Circular Saw

Make a diagram of the areas to be covered with new baseboard molding. Measure these lengths carefully and write down the measurements. Note if each cut is ending in an inside or outside corner, or if it is a straight cut with no angle.

Set up the sawhorses and lay your trim face down across them so the trim can be easily cut. Make sure you note the bottom and top of the trim.

Carefully measure the proper length on the back of the trim piece. Mark the line using the carpenter's square.

Adjust the circular saw blade to cut at the appropriate angle. For an inside corner, you will cut along the line you have marked on the back of the trim to the inside, so the cut will be the exact length of the measurement, angled inwards. For an outside corner, cut along this line towards an outside angle, so the piece is actually longer than your measurement.

Put all the pieces together to make sure the cuts have been made properly. Recut any pieces that don't fit before mounting to wall with trim nails. Use caulk to fill gaps and nail holes.