A crown molding calculator takes the guesswork out of ordering materials for trim work. Enter your room dimensions, corner count, and preferred crown profile to get exact linear footage, the number of sticks to buy, compound miter and bevel angles for every corner type, and a cost estimate — all before you step foot in the lumber yard.
Room Dimensions
Enter each wall length. Add walls until all sides of the room are covered.
Wall meets wall inward (typical room corners)
Wall protrudes outward (bay windows, columns)
Basic paint-grade ~$1–3/ft • Solid pine ~$3–6/ft • Hardwood ~$6–12/ft
Compound Miter Reference Chart
| Spring Angle | Corner Angle | Miter | Bevel |
|---|---|---|---|
| 38° | 90° corner (inside or outside) | 31.6° | 33.9° |
| 38° | 45° corner (octagon room) | 22.8° | 37.4° |
| 38° | 135° corner (bay window) | 40.9° | 29.3° |
| 45° | 90° corner (inside or outside) | 35.3° | 30.0° |
| 45° | 45° corner (octagon room) | 25.1° | 34.5° |
| 45° | 135° corner (bay window) | 44.3° | 25.6° |
Angles are for a compound miter saw with the crown molding lying flat on the saw table. Reverse the miter direction for left-hand vs right-hand cuts. Always verify with a test cut.
How to Use the Crown Molding Calculator
Installing crown molding transforms a plain room into something finished and polished — but buying the wrong amount or cutting at the wrong angle leads to wasted material and frustrating trips back to the store. This free crown molding calculator handles the math so you can focus on the cuts.
Step 1: Enter Your Room Dimensions
Choose between two input modes. Use Enter Wall Lengths if you have individual wall measurements — the calculator sums them into a perimeter automatically. Use Enter Perimeter Directly if you already measured the full room perimeter with a tape measure. For a basic rectangular room, perimeter = 2 × (length + width). The perimeter equals your base linear footage of crown molding needed.
Step 2: Count Your Corners
Every room has at least four inside corners (standard rectangular room). An inside corner is where two walls meet inward — the molding bends toward you. An outside corner is where the wall protrudes outward, like a bay window bump-out or a column. Count each corner type carefully because the miter and bevel angles flip between inside and outside cuts.
Step 3: Select Crown Profile and Waste Factor
Most residential crown molding sold at home centers has a 38-degree spring angle — this is the tilt of the molding from the wall when installed. Wider, more elaborate profiles are often 45 degrees. When in doubt, hold a scrap piece at 38 degrees against the wall and ceiling; if it seats flush, that is your spring angle. Set the waste factor to 10% for a simple rectangular room, 15% for rooms with closet openings or tray ceilings, and 20% for complex layouts with many corners.
Step 4: Review Linear Feet and Stick Count
The calculator shows your base linear footage, the total with waste added, and the number of sticks to purchase at your chosen stock length (8, 12, or 16 feet). Buying 16-foot lengths often reduces the number of joints on long walls and can be more economical per linear foot, even if the sticks are physically harder to handle solo.
Step 5: Use the Cutting Angles
The cutting angles table shows the compound miter and bevel settings for your selected spring angle. For inside corners, most finish carpenters cut one piece square (butt it into the corner) and cope the mating piece — tracing the crown profile with a coping saw so it overlaps the face of the first piece. For outside corners, compound miter cuts are used on both pieces. Set your miter saw to the listed miter angle, then tilt the blade to the bevel angle. Always make a test cut in a short scrap first.
Understanding the Cost by Grade
The cost breakdown table shows estimated totals across three grades of crown molding material. Paint-grade MDF or finger-jointed pine is the most affordable and is ideal when the finished piece will be painted. Mid-grade solid pine or poplar takes paint well and can also be stained lightly. Premium solid hardwood (oak, maple, cherry) is chosen for clear stain or natural finishes. Material cost is just part of the budget — if hiring a finish carpenter, labor typically adds $3–8 per linear foot on top of material.
FAQ
Is this crown molding calculator free?
Yes, the crown molding calculator is completely free with no usage limits. All calculations run locally in your browser — no signup, no account, and no data ever leaves your device.
Is my project data private?
Yes, everything is calculated entirely in your browser. Your room dimensions, corner counts, and cost estimates are never sent to any server or stored remotely.
How do I calculate linear feet of crown molding?
Add up the lengths of all walls in the room to get the perimeter. That perimeter is your base linear footage. Then add a waste factor — typically 10% for a simple rectangular room, 15% for rooms with many corners or angled walls — to account for cut-offs and mitered joints.
What are the correct miter and bevel angles for 90-degree crown molding corners?
For the most common 38-degree spring angle crown molding, a 90-degree inside or outside corner requires a miter saw set to 31.6 degrees miter and 33.9 degrees bevel. For 45-degree spring angle crown, the settings are 35.26 degrees miter and 30 degrees bevel. Always make a test cut in scrap before cutting finished pieces.
What is a spring angle for crown molding?
The spring angle is the angle at which the crown molding tilts away from the wall when installed. Most residential crown molding has a 38-degree spring angle. Premium profiles often use 45 degrees. The spring angle determines the compound miter and bevel angles needed to cut corners accurately.
How many pieces of crown molding will I need?
Divide your total linear footage (including waste) by the stick length you plan to buy — typically 8, 12, or 16 feet. The calculator rounds up to the nearest whole stick so you never run short. Buying 16-foot lengths reduces joints and is often more economical per linear foot.
What is the difference between a cope joint and a compound miter for inside corners?
A compound miter cuts both pieces at an angle to meet at the corner — fast to set up but can open up as the house settles. A cope joint cuts one piece square to the wall and then back-cuts (copes) the end of the mating piece to follow the profile of the first piece. Coped joints are more durable and are the preferred professional method because they don't show gaps if the wood moves.
How much does crown molding cost?
Crown molding ranges from about $1 to $3 per linear foot for basic paint-grade MDF or finger-jointed pine, $3 to $6 for medium-grade solid pine or poplar, and $6 to $12+ per foot for premium solid hardwood or wide architectural profiles. Material cost is just one part — installation labor (if hired out) typically adds $3 to $8 per linear foot.