How to Cut Molding Corners: Inside, Outside and Crown Angles

Cut outside corners as two opposite 45° miters, cope inside corners, and use (180 minus the wall angle) divided by 2 when a corner is out of square. Crown molding is the exception: cut it nested, upside down against the fence, at 45° with no bevel. This guide covers each corner type, the crown settings for 38° and 45° spring angles, and the saw-setting formula most guides skip.

Cutting Crown Molding Corners: Step-by-Step

Crown does not sit flat. It leans between the wall and the ceiling at its spring angle, so a plain 45° cut with the board lying down leaves a gap. There are two ways to fix that: hold the molding at its installed angle (the nested method, miter only) or lay it flat and dial in a miter and a bevel together. Nested needs one setting, so it is the one to learn first.

📊 Crown molding is typically sold in 45° and 38° spring-angle formats, and the angle decides the compound settings. Source: Wikipedia, Crown molding

Inside Crown Molding Corners (Coped Joint)

A coped end follows the profile of the first piece and stays tight even when the wall is a little out of square, by roughly 3 degrees according to trim guides.

1. Cut the first piece square at both ends and fit it tight into the corner.
2. Nest the second piece and cut a 45° inside-corner miter. The cut exposes the profile line you will follow.
3. Cope along that line with a coping saw, tilting the blade back so the cut undercuts the face (guides give roughly 5 to 15°). Only the front edge should touch the first piece.
4. Test the fit against the first piece. Pare high spots with a utility knife or a file, and leave the piece a little long until the cope fits.

A coping saw is the one tool a miter saw cannot replace here. Our guide to what a coping saw is used for covers blade direction and tension.

Outside Crown Molding Corners (Miter Joint)

Outside corners are always mitered, never coped. Cut both pieces at 45° nested, dry-fit them at the corner, and check that the points meet at the tip with no daylight on the ceiling edge. Glue the joint and pin it so it stays closed as the wood moves with the seasons.

How to Cut Crown Molding Corners the Easy Way (Flat Method)

Despite the heading, the nested method above is the simpler of the two. The flat method lays the crown on its back on the saw table and needs a miter and a bevel together. It earns its place for wide crown that will not nest under the fence. A double-bevel saw keeps the top of the molding against the fence for every cut, so you never flip the board. The settings are in the table further down.

How to Cut Crown Molding Corners

The Easiest Method: Nested (Upside-Down) Cuts

Nested means placing the crown upside down and backward, the way it sits against the wall and ceiling.

1. Find the two edges. One touches the ceiling, the other touches the wall. Pencil “C” on the back near the ceiling edge so you never mix them up.
2. Put the ceiling edge down on the saw table and the wall edge against the fence. The decorative face points toward you.
3. Set the miter to 45° for a 90° corner. Leave the bevel at 0.
4. Cut two scrap pieces and hold them together as a corner. If the joint is open or tight, move the angle by 0.5 to 1 degree and retest.
5. Cut the real pieces slightly long and trim to length after a test fit.

A crown stop or crown jig holds the molding at its spring angle so it cannot roll while the blade runs. That is why the product box above is a crown tool.

Inside Crown Molding Corners

If you miter an inside corner instead of coping it (fine on painted crown in a square room), the cut faces must meet at the back of the corner. Per DEWALT, for the nested method at 90°:

• Piece on the left wall: swing the saw to the right, 45 degrees, and keep the right-hand end of the board.
• Piece on the right wall: swing the saw to the left, 45 degrees, and keep the left-hand end of the board.

Outside Crown Molding Corners

The directions reverse for outside corners, because the mitered faces must wrap around the corner and meet at its tip.

• Piece on the left wall: swing the saw to the left, 45 degrees, and keep the right-hand end of the board.
• Piece on the right wall: swing the saw to the right, 45 degrees, and keep the left-hand end of the board.

Measure the real corner with an angle finder first, and use the out-of-square formula below if it is not 90°.

Compound Miter Settings (Flat Method for 52/38 Crown)

If you lay the molding flat, the saw needs both a miter and a bevel. These are the settings for a square 90° corner. They flip left and right, and which end you keep, between inside and outside corners. For any corner that is not 90° the numbers change, so use a crown calculator and test on scrap.

Crown spring angle	Miter angle (90° corner)	Bevel angle (90° corner)
52/38 (common US profile)	31.6°	33.9°
45/45	35.3°	30°

Many saws mark 31.6° and 33.9° on a crown detent scale for the 52/38 profile. DEWALT stresses pretesting every setup on scrap, because these angles are precise and hard to set exactly (DEWALT crown molding guide).

Understanding The Different Types Of Corners

Inside Corners Vs. Outside Corners

• Inside corner: two walls meet in a concave angle, like the corner of a room. The trim pieces meet in the recess.
• Outside corner: two walls meet in a convex angle that sticks out into the room, like a chimney breast or a soffit. The trim wraps around it and the joint is in full view.

Coping Vs. Mitering Corners

A cope shapes the end of one piece to match the profile of the other. It beats mitering inside corners on stained or clear-coated trim because it tolerates out-of-square walls and seasonal movement. Outside corners cannot be coped, so they are always mitered.

Joint	Best for	Difficulty	Gap risk
Cope (inside corner)	Stained trim, uneven walls	Moderate	Low, adjusts to the wall angle
Miter (inside corner)	Painted trim, square walls	Easy	Medium, opens if the wall is not square
Miter (outside corner)	Every outside corner	Easy to moderate	Medium, shows if the angle is off
Scarf joint	Splicing a long run on one wall	Easy	Low with a full overlap
Butt joint plus caulk	Quick painted installs	Easy	Hidden by caulk

Cutting Inside Corner With Coping Technique

Same cope as the crown section, applied to flat trim such as baseboard, held upright with its back against the fence.

1. Fit the first piece square into the corner. It runs wall to wall.
2. Cut the second piece at 45° in the inside-corner direction so the cut face points into the corner and the profile edge shows on the front.
3. Follow the profile with the coping saw, angling the blade slightly back so the cut undercuts the face.
4. Test the coped end against the first piece, file the contact points, and nail once it closes.

Use the sizes in our trim and baseboard nail size chart so the nails do not split the cope.

Cutting Inside Corner With Mitered Technique

A mitered inside corner uses two matching 45° cuts. Stand each piece the way it sits on the wall, back against the fence, and swing the saw so the long point of each cut is on the back, touching the wall. The face is the short point.

1. Measure wall to wall along the back edge of the trim. That is the long point of the miter.
2. Set the saw to 45° for a square corner, or to the result of the formula below if the corner is not 90°.
3. Cut a scrap pair first and check that the two cut faces close with no daylight.
4. Cut the real pieces, dry-fit them, then nail and caulk the joint if the trim is painted.

If the joint opens at the front, the corner is probably tighter than 90°. Our quarter round cutting guide uses the same long-point rules at a smaller scale.

Cutting Outside Corner With Mitered Technique

An outside corner is mitered, one cut on each piece, swung in opposite directions. With the back against the fence, an outside-corner miter leaves the long point on the face, so the pieces wrap past the wall corner and meet at the tip.

1. Measure to the wall corner and add the thickness of the trim, because the long point sticks out past the wall.
2. Set the saw to 45° (or the formula result) and swing it the opposite way from an inside corner.
3. Cut the mating piece as a mirror image and hold both against the wall. If the points miss, change the angle by a half degree and retest on scrap.
4. Glue the joint and pin it with small brads or 23 gauge pins so it stays closed as the wood moves.

Why You Do Not Cope An Outside Corner

Coping works by tucking one piece against the face of another that runs into the corner. An outside corner has no piece to tuck against, only two ends that must meet at a point, so a miter is the only joint that closes it. For more on outside corners on baseboard specifically, see our guide to outside corner baseboard molding.

Crown vs Baseboard vs Casing: How the Cut Changes

Molding	How it sits on the saw	Inside corner	Outside corner
Crown	Nested: ceiling edge on the table, wall edge on the fence (or flat with compound settings)	Cope, or nested miter	Nested miter
Baseboard	Upright, back against the fence, bottom on the table	Cope, or miter if painted	Miter
Door casing	Face up, flat on the table, mitered across its width	Not used	Mitered at the head corners

For the baseboard column in detail, see our guide to cutting baseboards with a miter saw or the baseboard corner angle guide. For crown only, with cope angles and cabinet-top applications, see crown molding corners: miter, cope and cabinet angles.

Out-of-Square Corners: The (180 Minus Wall Angle) / 2 Formula

Most rooms have at least one corner that is not 90°. A 45° miter on that corner leaves a wedge-shaped gap. Measure the real corner with a digital angle finder or protractor, then use this: saw setting = (180 minus the wall angle) divided by 2. A square corner gives (180 minus 90) / 2 = 45°. An 88° corner gives (180 minus 88) / 2 = 46°.

Measured wall angle	Saw setting per piece	Working
87° (tight)	46.5°	(180 minus 87) / 2
88°	46°	(180 minus 88) / 2
90° (square)	45°	(180 minus 90) / 2
92°	44°	(180 minus 92) / 2
93° (open)	43.5°	(180 minus 93) / 2
120°	30°	(180 minus 120) / 2
135° (bay or angled wall)	22.5°	(180 minus 135) / 2

This also corrects a common shortcut that says to halve the corner reading and set the saw to that number. That only works at exactly 90°. On a 135° corner it would give 67.5°, when the right setting is 22.5°. A few saws mark angles from the other side, so a scrap test settles whether your scale reads 0 as a square cut.

For nested crown the same plan-view geometry applies, so the miter setting follows the same formula, but test it on scrap because crown is less forgiving than flat trim.

Tools And Materials Needed For Cutting Molding Corners

• Miter saw with a fine-tooth finish blade, to leave a clean face on the cut.
• Coping saw with a fine blade for inside corners.
• Angle finder or protractor to measure the real wall angle.
• Crown stop or jig if you cut crown nested.
• Wood glue and a brad nailer or pins for outside miters.
• Paintable caulk for small gaps on painted trim.

Safety: hold the molding firmly, keep your hand clear of the blade path, and wear eye and hearing protection.

Common Mistakes To Avoid When Cutting Molding Corners

• Swinging the saw the wrong way. Inside and outside miters use opposite directions. A scrap pair that overlaps instead of closing means you swung it backward.
• Measuring to the short point. On an inside corner measure along the back, which is the long point. Measuring to the short point cuts the piece short by about the width of the profile.
• Using 45° on every corner. Use the formula when the corner is not square.
• Skipping the scrap test. A half degree is enough to open a joint on a small profile.
• Mitering an inside corner on stained trim. Cope it instead, because a miter opens as the wood moves.
• Filling a big gap. Caulk and wood putty hide small gaps only. If an outside miter has opened, reglue the miter joint or recut the piece.

Keep reading

• How to Cut Inside Corner Crown Molding (Coped Joint Method)
• Cut Crown Molding Corners on a Table Saw (52°/38° Angle Guide)
• How to Cut Quarter Round for a 90-Degree Corner (Miter or Cope)

Frequently Asked Questions For How To Cut Molding Corners

How Do You Cut Perfect Molding Corners?

Measure the real corner, set the saw to (180 minus that angle) divided by 2, and swing it the right way for an inside or outside corner. Test a scrap pair first. On stained trim, cope inside corners.

What Angle Do You Cut Corner Molding?

Cut 45 degrees on each piece for a square 90 degree corner. If the corner is not square, use (180 minus the corner angle) divided by 2. Crown molding cut nested also uses 45 degrees, with no bevel.

How Do You Cut A 90 Degree Corner Trim?

Cut two matching 45 degree miters, swinging the saw opposite ways for inside and outside corners. On an inside corner you can instead cope the second piece after a 45 degree cut.

How Do You Cut Miter Corners For Trim?

Stand the trim on the saw as it sits on the wall, cut one piece, then cut the mating piece as a mirror image. Dry-fit both, then glue and pin the joint.

Should You Cope Or Miter Crown Molding Inside Corners?

Cope the inside corners on stained or clear-coated crown, because a coped joint stays tight on walls that are slightly out of square. A plain miter is acceptable on painted crown in a square room. Outside corners are mitered.

Conclusion

Miter outside corners, cope inside corners, and measure before you trust 45 degrees. For crown, nest it and keep the saw at 45 degrees. Test every setting on scrap from the same run.