Crown Molding and Baseboard: Linear Feet, Waste, and Miter Angles

Counting Length and Waste

List each wall and round up to the next inch. For baseboard, subtract the width of doorways and add back the short returns at closets. Plan each piece to run between corners, since long walls are best covered with a single stick when possible to avoid visible joints. If a wall is longer than your longest stock piece, join two pieces with a scarf joint (a 45-degree cut) over a stud. Add 10% for simple rooms and 15% or more for rooms with many corners, bay windows, or crown molding with complex cuts. Buy one extra stick for practice cuts.

For a room with walls of 12, 14, 12, and 14 feet, using 8-foot sticks: the 12-foot walls need two sticks each with an offcut, or 12-foot stock can avoid a seam.

Miter Angles

Where two walls meet at 90 degrees, each piece of baseboard is cut at 45 degrees on an outside corner so the two pieces form a right angle. The general rule is that the miter angle for each piece is half the corner angle: for a 90-degree corner, 45 degrees; for a 135-degree corner (a bay window or angled wall), 22.5 degrees. For inside corners, carpenters often cope one piece: they cut the end of the first piece square and butt it into the corner, and cut the second to match the profile of the first with a coping saw. Coping stays tight when walls are not perfectly square or when wood moves with humidity, where mitered inside corners tend to open.

Crown molding sits at a spring angle (commonly 38 or 52 degrees to the wall) and requires compound cuts, or cutting the molding upside down and backward against the saw fence so that a simple 45-degree setting works.

Installation Tips

Find studs and nail trim into them with a finish nailer or finish nails every 16 inches. Prime and paint trim before installation when possible, then fill nail holes and caulk the joint with paintable caulk. Use a stud finder, a level for baseboard along sloping floors (scribe the bottom if gaps are large), and a miter gauge to check actual wall angles, which are often not exactly 90 degrees. For crown, use cleats or blocking to support the top edge. Cut slightly long and trim to fit. Test cuts on scrap.

Estimating Cost

Pine and MDF baseboard cost roughly $1 to $4 per linear foot, hardwoods more, and crown molding $2 to $10 or more depending on profile and material, with polymer and foam options available. For a 52-foot room with 57 feet of crown at $5 per foot, material costs $285, plus caulk, nails, paint, and corner blocks. Labor for crown is often $5 to $15 a linear foot if hired. Use the same method for chair rail, picture rail, and shoe molding.