Miter Angle Calculator
Find the miter saw setting for any corner — a flat miter for trim and frames, or a compound miter-plus-bevel for sprung crown molding cut flat on the saw table. Enter the corner angle, pick inside or outside, and (for crown) the spring angle, and get the miter and bevel settings, the cut angle from the edge and the long-point offset — with by-corner and by-spring tables, a chart, and a downloadable PDF.
| Corner | Miter | Bevel | Cut from edge |
|---|---|---|---|
| Enter a cut to compare | |||
| Spring | Crown type | Miter | Bevel |
|---|---|---|---|
| Enter a cut to compare | |||
How to use the miter angle calculator
Four quick steps turn a corner into saw settings — a flat miter for trim, or a compound miter-plus-bevel for sprung crown molding cut flat on the saw — with the cut angle from the edge and the long-point offset.
Pick the cut type
Flat miter for trim and frames, or crown for compound molding.
Enter the corner
The wall corner angle, and whether it’s an inside or outside corner.
Set spring or width
The crown spring angle, or the board width for a flat miter.
Read results & save a PDF
Get the miter and bevel settings — then download a report.
The formulas behind the settings
A flat miter is half the turn with no bevel; a crown cut flat on the saw needs both a miter and a bevel from the spring and corner angles.
▶ Worked example
A 38/52 crown (38° spring) on a square 90° inside corner, cut flat on the saw.
Miter = arctan(sin 38° × tan 45°) = 31.62°; bevel = arcsin(cos 38° × cos 45°) = 33.86°.
Crown 38/52 at 90° → miter 31.62° · bevel 33.86°
As a flat miter the same corner is simply (180 − 90) ÷ 2 = 45° with no bevel; a 45/45 crown would be 35.26° and 30°.
Miter angle quick reference
The cut formulas, the crown settings by corner angle, and the crown settings by spring angle for a square corner.
| Quantity | Formula |
|---|---|
| Flat miter | (180 − corner) ÷ 2 |
| Crown miter | arctan(sin(spring) × tan(corner ÷ 2)) |
| Crown bevel | arcsin(cos(spring) × cos(corner ÷ 2)) |
| Cut angle from edge | 90 − miter |
| Long–short offset (flat) | width × tan(miter) |
| Corner | Shape | Miter | Bevel |
|---|---|---|---|
| 60° | Triangle corner | 19.57° | 43.03° |
| 90° | Square | 31.62° | 33.86° |
| 120° | Hexagon | 46.84° | 23.20° |
| 135° | Octagon | 56.07° | 17.55° |
| 150° | Dodecagon | 66.48° | 11.77° |
| Spring | Crown | Miter | Bevel |
|---|---|---|---|
| 30° | 30/60 | 26.57° | 37.76° |
| 38° | 38/52 | 31.62° | 33.86° |
| 45° | 45/45 | 35.26° | 30.00° |
| 52° | 52/38 | 38.24° | 25.81° |
| 60° | 60/30 | 40.89° | 20.70° |
The two common US crowns are 38/52 and 45/45; a 45/45 crown on a square corner is the classic 35.26° miter / 30° bevel. A flat miter is the same corner with the bevel at 0° — a 90° corner is 45°.
Everything the calculator returns
One calculation gives the full cut picture — both saw settings and the geometry for your corner.
Miter settings at a glance
The settings that matter most, and the default result.
Built for the way you work
Whether you are running crown, fitting trim, or opening up a remodel, the saw settings start from the same corner.
Cutting sprung crown flat on the saw and need the compound miter and bevel for the real corner and spring angle.
- Read the spring off the molding
- Set both miter and bevel
- Mirror for the opposite piece
Fitting flat trim to corners that are rarely square and want the exact miter for each one, plus the offset to mark it.
- Measure the real corner
- Cut half the turn
- Use the offset to mark
Putting up crown or trim for the first time and want the saw settings in plain numbers before cutting good material.
- Start with 38/52 or 45/45
- Try flat vs crown
- Always test on scrap
Cut crown and trim that fit
Seven things that make a compound or flat miter close up clean.
Crown cut flat needs two angles
Lying crown flat on the table trades holding it sprung for a compound cut — you set both a miter and a bevel, not just one.
Know your spring angle
The settings depend on it. Read 38/52 or 45/45 off the back of the molding or the box — don’t assume.
45/45 at 90° is 35.26 / 30
The classic compound-crown numbers. Worth memorizing, but recheck when the corner isn’t square.
Measure the real corner
Walls are seldom a true 90°. An angle finder on the actual corner beats assuming square and chasing gaps later.
Mirror the two pieces
The two halves of a corner are mirror images — same angles, opposite hands. Flip the stock or swing the miter the other way.
Inside and outside are the same size
The angle magnitudes match; you just keep the opposite side of the line and swap which piece goes where.
Always test on scrap
Compound cuts are easy to mirror wrong. Cut a scrap corner and check the fit before touching finished molding.
Frequently asked questions
Common questions about miter and bevel settings, crown spring angles, and flat versus compound cuts.
Crown molding cut flat on the saw table needs two settings — a miter and a bevel — because the molding is sprung at an angle to the wall. The miter is the arctangent of the sine of the spring angle times the tangent of half the corner angle. The bevel is the arcsine of the cosine of the spring angle times the cosine of half the corner.
The spring angle is the angle between the crown and the wall, printed on the molding; the corner angle is the wall corner. Both settings come from those two numbers.
For example, a 38/52 crown (38 degree spring) on a square 90 degree corner needs a 31.62 degree miter and a 33.86 degree bevel. This calculator gives both settings for any crown and corner, or a flat miter for ordinary trim.
They are the two angles you set on a compound miter saw to cut sprung crown lying flat on the table. The miter is the angle the saw swings left or right; the bevel is the angle the blade tilts from vertical. Together they produce the compound cut that fits the corner.
Both depend on the spring angle of the crown and the corner angle. For the two common US crowns on a square corner, a 38/52 crown takes about a 31.6 degree miter and a 33.9 degree bevel, and a 45/45 crown takes 35.26 degrees and 30 degrees.
Cutting crown flat this way avoids holding it sprung against the fence, but it is why crown needs both settings. This calculator lists the miter and bevel for your crown and corner.
The spring angle is the angle between the back of the crown and the wall when it is installed — how far the molding leans out from vertical. It is set by the profile and printed on the molding or its box, not something you choose.
The two common US crowns are 38/52 and 45/45. A 38/52 crown has a 38 degree spring angle (and sits 52 degrees off the ceiling); a 45/45 crown springs at 45 degrees. The spring angle drives both the miter and the bevel settings for a flat cut.
For example, at a 90 degree corner a 38 degree spring gives a 31.62 degree miter, while a 45 degree spring gives 35.26 degrees. This calculator includes 30, 38, 45, 52 and 60 degree springs, or you can type your own.
A flat miter is a single angled cut with the blade straight up — the bevel is zero. It is what you use for baseboard, casing, picture frames and any trim that lies flat against the wall. The setting is simply 180 degrees minus the corner, divided by two.
A compound cut combines a miter with a bevel, and is needed for sprung crown molding cut flat on the saw table, because the crown sits at an angle to both the wall and the ceiling. Both the saw swing and the blade tilt change.
For example, a flat 90 degree corner is a 45 degree miter with no bevel; a 38/52 crown at the same corner is a 31.62 degree miter and a 33.86 degree bevel. This calculator does both — pick flat or crown.
For a 45/45 crown molding on a square 90 degree corner, cut flat on the saw, set the miter to 35.26 degrees and the bevel to 30 degrees. These are the classic compound-crown numbers every finish carpenter memorizes.
The 35.26 degree miter and 30 degree bevel apply to both pieces of the corner; you mirror them — swing the miter the opposite way, or flip the stock — for the two halves, and the same sizes serve inside and outside corners.
For example, this calculator returns exactly 35.26 degrees and 30 degrees for a 45 degree spring at a 90 degree corner, and recalculates both if your corner is not square. Always confirm on a scrap test cut.
An inside corner is where the walls turn into the room — the usual corner, where the molding wraps into a concave angle. An outside corner is where a wall projects out, like a bump-out or a column, and the molding wraps around a convex angle.
The miter and bevel angles are the same size for both; what changes is which side of the cut line you keep and how you mirror the two pieces. On an inside corner the long point is at the back; on an outside corner it is at the face.
For example, a 90 degree corner gives the same angle magnitudes inside or out — you just cut the opposite side and swap the pieces. This calculator gives the settings and you mirror them for the corner type.
Measure the actual corner, because walls are rarely a true 90 degrees. Use an angle finder or a protractor to read the real corner angle, then let the miter and bevel follow from it — for a flat miter each piece takes half the error, and for crown both settings shift.
A corner that is a couple of degrees off square changes the settings by a small but real amount, enough to open a gap in a tight joint. Measuring beats assuming 90.
For example, this calculator takes any corner from 1 to 179 degrees and recalculates the miter and bevel, so an 88 or 92 degree corner is no harder than a square one. Always test-cut on scrap before the finished molding.
Very open corners and some crown setups call for a miter past the roughly 45 to 50 degree range of many saws. A 150 degree corner, for instance, needs a 66 degree crown miter at a 38 degree spring, beyond what a lot of saws reach.
The fixes are to cut it in two passes, use a sliding compound saw with a wider range, or make a jig that holds the stock at an offset so the blade reaches the angle. A table saw sled is another option for steep cuts.
This calculator flags when a miter is past the typical saw range so you know to plan the cut differently. Always test the setup on scrap first.
Disclaimer: US units (degrees, inches). Flat miter = (180 − corner) ÷ 2 with the bevel at 0°. Crown molding cut flat on the saw table: miter = arctan(sin(spring) × tan(corner ÷ 2)); bevel = arcsin(cos(spring) × cos(corner ÷ 2)). The spring angle is the angle between the crown and the wall — 38/52 and 45/45 are the common US crowns. Real walls are rarely exactly 90°, so measure the actual corner with an angle finder, mirror the two pieces, and account for the corner being inside or outside. A layout aid only — always test-cut on scrap before cutting finished molding.