What is the miter angle for a 90-degree corner?

For a standard 90° corner, set your miter saw to 45°. The formula is: miter angle = corner angle ÷ 2. Each piece gets a 45° cut so that the two angled faces meet flush at the corner.

What is a compound miter cut?

A compound miter has two angles simultaneously: the miter (horizontal rotation of the saw table) and the bevel (tilt of the saw blade). Crown molding is almost always cut as a compound miter because the molding sits tilted against both the wall and ceiling.

What spring angle should I use for crown molding?

Most crown molding profiles have a spring angle of either 38° or 45°. The spring angle is stamped or printed on the back of the molding. A 45° spring molding is the most common in residential trim work.

What is an inside vs outside corner?

An inside corner faces inward — like the interior corner of a room wall. Its corner angle is typically 90°. An outside corner faces outward — like the exterior corner of a cabinet or bay window projection. Outside corners have an effective corner angle greater than 90°, often 270° minus the measured angle. This tool uses the angle between the two wall faces as seen from above; enter the actual measured angle.

Why does the calculator give two different angles for compound cuts?

Compound miter geometry yields a blade tilt AND a miter table angle. Both must be set on your saw at the same time. The values shown are for a saw with a positive bevel direction — if your saw tilts the other way, use the same numbers but flip the bevel direction toggle on the saw.

How do I measure the corner angle in a room?

Place a T-bevel or digital angle finder flat on the floor into the corner and read the angle. Most interior rooms measure between 88° and 92° due to construction tolerances, so never assume exactly 90°.

Miter Angle Calculator

Name: Miter Angle Calculator
Availability: InStock
Author: Nham Vu

Calculate the miter saw angle to cut molding or trim for any corner, including compound miter angles for sloped ceilings and crown molding.

For flat trim: baseboard, door casing, picture frames. Blade stays vertical.

Corner Dimensions

Corner Angle (degrees) — angle between the two walls

Standard room corner = 90°. Outside corner = measured angle.

Quick Corner Presets

Saw Settings

Miter Table Angle

—

set on saw table (both pieces)

Blade Bevel

0°

blade stays vertical

Parameter	Value
Corner Angle	—
Spring Angle	—
Half Corner Angle	—
Miter Table Angle	—
Blade Bevel Angle	—
Cut Direction	—

How the Formula Works

1
Measure the corner: Find the angle between the two surfaces using a digital angle finder or T-bevel. A standard room corner is 90°.
2
Simple miter formula: Miter Angle = Corner Angle ÷ 2. For a 90° corner: 90 ÷ 2 = 45°. Each piece is cut at 45° so the two faces meet flush.
3
Compound miter — miter angle: For compound cuts: Miter = arctan(cos(spring) × tan(half-corner)). The spring angle describes how far the molding tilts off the wall.
4
Compound miter — bevel angle: Bevel = arcsin(sin(half-corner) × sin(spring)). Both the miter table and blade tilt must be set simultaneously on the saw.
5
Left and right pieces: Both pieces at a corner get the same angle magnitudes — just mirror the direction. Flip your workpiece face-up vs. face-down, or use the opposite miter direction on the saw.
6
Test cut first: Cut scrap pieces at the calculated angles and dry-fit them before cutting finished trim. Walls are rarely perfectly plumb or square.

Summary

Calculate the miter saw angle to cut molding or trim for any corner, including compound miter angles for sloped ceilings and crown molding.

How it works

Select Simple Miter for flat baseboard or casing, or Compound Miter for crown molding on a sloped ceiling.
Enter the corner angle — typically 90° for a standard room corner, but any angle from 1° to 179° is supported.
For compound cuts, enter the spring angle (the tilt of the molding against the wall) — 38° and 45° are the most common crown molding profiles.
Click Calculate to get the blade tilt and miter table angle to set on your saw.
The results show angles for both the left and right pieces meeting at the corner.
Use the copy buttons to save values before heading to the saw.

Use cases

Setting miter saw angles for baseboard trim at inside or outside corners.
Cutting crown molding flat on the saw table using compound miter angles.
Framing picture frames with precise 45° miters.
Fitting door and window casing around non-square corners in older homes.
Calculating molding cuts for octagonal or hexagonal frames.
Installing chair rail or wainscoting cap at odd-angle wall intersections.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu