Miter Angle Calculator

Calculate precise miter and bevel angles for perfect corner joints in your woodworking projects.

Select your calculation type below. For standard corner joints, use the "Corner Angle" calculator. For complex joints like crown molding, use the "Crown Molding" calculator.

Calculation Type

Corner Angle Calculator

Corner Angle (degrees)

Number of Sides (optional, for polygons)

About Our Miter Angle Calculator

Our Miter Angle Calculator is a specialized tool designed for woodworkers, carpenters, and DIY enthusiasts. It helps determine the precise angles needed for cutting materials to create tight, professional-looking joints at corners and intersections.

What Are Miter Angles?

A miter angle is the angle at which you need to cut your material to create a joint where two pieces meet at a corner. For a standard 90° corner (like the corner of a picture frame), each piece is cut at a 45° angle so they fit together perfectly. For non-standard corners, calculating the correct miter angle is essential for a proper fit.

Understanding the Calculations

This calculator provides two main calculation types:

Standard Corner Calculation: For basic miters where two pieces meet at a corner (like trim, baseboards, picture frames)
Crown Molding Calculation: For compound angle cuts needed when installing crown molding that sits at an angle between the wall and ceiling

Standard Miter Formula

For a standard corner joint, the miter angle is calculated as:

Miter Angle = (180° - Corner Angle) ÷ 2

For example, with a standard 90° corner, the miter angle would be:

(180° - 90°) ÷ 2 = 45°

Crown Molding Compound Angles

Crown molding requires compound angles (both miter and bevel) because the molding sits at an angle between the wall and ceiling. The calculations are more complex and depend on:

The angle of the corner where walls meet
The "spring angle" of the crown molding (the angle at which it sits against the wall/ceiling)

Key Features:

Calculate precise miter angles for any corner angle
Determine compound angles for crown molding installation
Calculate angles for regular polygon constructions
Provide both miter and bevel angles for compound cuts
Support for standard and custom crown molding spring angles

Application Areas:

Trim Work: Baseboards, door and window casings, chair rails, and other decorative trim

Picture Frames: Creating frames with various corner angles

Crown Molding: Ceiling trim installation with compound angles

Furniture Making: Building cabinets, tables, and other wooden furniture

Polygon Projects: Creating multi-sided objects like planters, tables, or decorative items

Tips for Perfect Miter Joints

Always measure and mark your workpiece carefully before cutting
Use a quality miter saw with a sharp blade for cleaner cuts
Make test cuts on scrap material before cutting your actual workpiece
Consider using a miter box for hand saw cuts to maintain consistent angles
For crown molding, position the piece in the saw exactly as it will sit on the wall/ceiling
Use wood glue and finishing nails for stronger joints

Whether you're a professional woodworker or a DIY enthusiast, this calculator helps you achieve professional results with perfectly aligned corners and joints in your projects.

Frequently Asked Questions

What's the difference between miter angle and bevel angle?

A miter angle is a horizontal angle cut across the face of the material, while a bevel angle is a vertical angle cut through the thickness of the material. Standard miter saws cut miter angles by rotating horizontally, while compound miter saws can also tilt to cut bevel angles. Compound cuts involve both miter and bevel angles and are often used in crown molding and complex joinery.

Why are my miter joints not fitting perfectly despite using the calculator?

Several factors can affect the fit of miter joints: 1) Saw calibration - ensure your saw is properly calibrated and the blade is at exactly 90° to the table when set to 0°; 2) Material issues - warped or bowed materials won't create clean joints; 3) Measurement errors - even small measurement errors can result in gaps; 4) Cutting technique - blade deflection or movement during cutting can affect precision. Always make test cuts first and consider using a miter jig for improved accuracy.

What is a spring angle in crown molding?

The spring angle (or crown angle) refers to the angle at which crown molding sits between the wall and ceiling. Standard crown molding typically has a 38°, 45°, or 52° spring angle. This is the angle formed between the back of the molding and the wall when installed. The spring angle is crucial for calculating the compound miter and bevel angles needed for proper cuts, especially at corners. You can determine your crown's spring angle by holding it against the wall in its installation position and measuring the angle.

How do I calculate angles for a regular polygon?

For a regular polygon with n sides, the interior angle is (n-2)×180°÷n, and the exterior angle is 360°÷n. To create a regular polygon, you need to cut each piece at a miter angle of half the exterior angle. For example, for a hexagon (6 sides), the exterior angle is 360°÷6 = 60°, so each piece should be cut at a 30° miter angle. Our calculator can determine these angles automatically when you enter the number of sides.