Miter Angle Calculator

The miter angle is the angle at which you cut material so two pieces join to form a corner. The principle is simple but essential:

The Basic Formula:

Miter Angle = Corner Angle ÷ 2

Common Corner Angles:

How It Works: When two pieces meet at a corner, each piece contributes half the angle. Think of it like two pizza slices meeting—each slice has an angle that's half the total corner angle.

Saw Setting vs. Cut Angle: Miter saws are calibrated in degrees from 0° (perpendicular cut). The "miter angle setting" is how far you rotate the blade from perpendicular:

• 0° setting = 90° cut (square end)
• 45° setting = 45° cut (standard miter)
• 90° setting = 0° cut (would be parallel to the fence, not possible)

Why Accuracy Matters: A 1° error might seem insignificant, but on a 12-foot baseboard:

• 1° error = 1/4" gap at the corner
• 2° error = 1/2" gap at the corner
• 5° error = 1"+ gap—completely unusable

Understanding the three types of angled cuts is essential for trim work:

Miter Cut (Horizontal Rotation): The blade pivots left or right relative to the fence, cutting an angle across the face of the material. The cut is perpendicular to the face but angled relative to the length.

Bevel Cut (Vertical Tilt): The blade tilts toward or away from vertical, cutting an angle through the thickness of the material. The cut is at an angle to the face.

Compound Cut (Both Miter AND Bevel): Combines both angles simultaneously. Essential for crown molding, cove molding, and any trim that sits at an angle to the wall.

Miter Saw Capabilities:

Crown molding requires compound miter cuts because the material sits at an angle (spring angle) between the wall and ceiling. Here are the settings for common scenarios:

Spring Angle Explained: The spring angle is the angle between the back of the crown and the wall:

• 38° Spring (52/38): Most common—the crown projects 52° from ceiling, sits 38° from wall
• 45° Spring: Simpler math, less projection

Compound Miter Settings for 90° Corners:

38° Spring Crown (Most Common):

45° Spring Crown:

Non-90° Corner Compound Angles (38° Spring):

Nested Crown Technique: Instead of compound cuts, you can place crown molding flat (upside down and backwards) against the fence and table:

• Bottom edge against fence
• Top edge on table
• Cut simple miter angles (no bevel)
• Works well for crown up to 5" width

Building multi-sided frames, planters, or decorative pieces requires specific miter angles:

Polygon Miter Formula:

Interior Angle = 180° × (n - 2) ÷ n
Miter Angle = Interior Angle ÷ 2

Where n = number of sides

Common Polygon Angles:

*Angles beyond most saw ranges—use complementary angle technique

Complementary Angle Technique: When the required angle exceeds your saw's range (typically 50-55°):

Complementary Angle = 90° - Required Angle

For a 67.5° cut (octagon):

• Complementary = 90° - 67.5° = 22.5°
• Set saw to 22.5° and flip the workpiece

Polygon Construction Tips:

Most corners in homes aren't exactly 90 degrees. Here's how to measure accurately:

Angle Measuring Tools:

How to Measure a Corner:

1. Place the angle finder legs flat against both walls
2. Read the angle displayed (or lock the T-bevel)
3. For T-bevel: Transfer to a protractor or directly to saw
4. Divide by 2 for miter angle

Common Angle Variations:

Calculating Miter for Non-90° Corners:

Testing Before Cutting:

1. Cut two scrap pieces at calculated angle
2. Hold together at corner
3. Check gap with light behind joint
4. Adjust ±0.5° and retest if needed

Even new miter saws can be slightly out of calibration. Regular checks prevent wasted material:

Checking 90° (Square) Calibration:

1. Set saw to 0° miter, 0° bevel
2. Cut a piece of scrap
3. Place cut end against a known-square reference
4. Gap indicates error direction
5. Adjust positive stops or accept offset

Checking 45° Calibration:

1. Set saw to 45° miter
2. Cut two pieces of scrap
3. Join pieces at corner—should form 90°
4. Check with combination square
5. Adjust if needed

Common Calibration Issues:

Calibration Frequency:

Using Angle Detents: Most miter saws have positive stops (detents) at common angles:

• 0°, 15°, 22.5°, 31.6°, 45°
• These are typically more accurate than freehand settings
• Use detents when possible, verify if critical

Choosing the right miter saw affects accuracy, capacity, and ease of use:

Miter Saw Types (2026 Prices):

Cutting Capacity Comparison:

Key Features to Consider:

Popular 2026 Models:

When miter joints don't fit properly, systematic troubleshooting identifies the cause:

Gap at the Front (Toe Gap):

Gap at the Back (Heel Gap):

Gap Along Entire Joint:

Crown Molding Specific Issues:

Quality Check Process:

1. Make test cuts on scrap
2. Check joint against light
3. Measure gap with feeler gauge
4. Adjust angle in small increments (0.25-0.5°)
5. Repeat until perfect
6. Cut actual pieces

Acceptable Tolerances:

Professional techniques for complex joints and situations:

Coped Joints for Inside Corners: An alternative to mitering inside corners on baseboards and crown molding:

1. Cut first piece square (90°)—install it tight to corner
2. Cut second piece at 45° miter
3. Use coping saw to follow the profile
4. Remove back material at 45° angle
5. Fit coped end against first piece

Benefits of Coping:

Scarf Joints for Long Runs: When molding isn't long enough for the wall:

1. Cut both pieces at 45° miter (not 90° butt)
2. Overlap joints with grain direction
3. Place joint over stud for backing
4. Glue and pin both pieces

Back-Beveling: Slightly beveling the back of miter cuts improves joint appearance:

1. Set bevel 1-2° off square
2. Creates slight undercut on back
3. Front edge closes tightly first
4. Minor gaps hidden at back

Return Cuts (End Caps): For baseboards and crown that end without meeting another piece:

1. Cut main piece with 45° miter
2. Cut short "return" piece to match
3. Glue return to create finished end
4. Sand smooth after drying

Micro-Adjustment Technique: For stubborn gaps:

1. Hold joint together, mark gap location
2. Identify which side needs material removed
3. Set saw to slightly steeper angle (0.25-0.5°)
4. Take light pass—remove shaving, not board
5. Retest and repeat if needed