📐 Miter Angle Calculator
Calculate miter angle for corners and polygons
Angle of the corner being mitered
How to Use This Calculator
Select Calculation Type
Choose to calculate from corner angle (for any corner) or from number of sides (for regular polygons). Number of sides is useful for frames and regular shapes.
Enter Angle or Sides
If calculating from corner angle, enter corner angle in degrees (e.g., 90° for square corner). If calculating from sides, enter number of sides (e.g., 4 for square, 6 for hexagon).
Calculate and Review
Click "Calculate Miter Angle" to see miter angle, corner angle, complementary angle, and number of sides (if applicable). Use miter angle to set your saw.
Set Saw
Set your miter saw to the calculated miter angle. For example, 45° miter angle means set saw to 45°. Cut both pieces at the same miter angle for a perfect corner.
Formula
Miter Angle = Corner Angle / 2
Corner Angle (polygon) = 180 × (n-2) / n
where: n = number of sides
Example 1: Square Corner (90°)
Step 1: Miter Angle = 90 / 2 = 45°
Step 2: Set saw to 45° for square frame
Example 2: Hexagon (6 sides)
Step 1: Corner Angle = 180 × (6-2) / 6 = 180 × 4 / 6 = 120°
Step 2: Miter Angle = 120 / 2 = 60°
Step 3: Set saw to 60° for hexagon frame
Example 3: Octagon (8 sides)
Step 1: Corner Angle = 180 × (8-2) / 8 = 180 × 6 / 8 = 135°
Step 2: Miter Angle = 135 / 2 = 67.5°
About Miter Angle Calculator
The Miter Angle Calculator is an essential tool for carpenters, woodworkers, and framers who need to calculate miter angles for corners, frames, and regular polygons. This calculator implements geometric formulas to determine miter angle from corner angle or number of sides, helping you set your saw accurately for perfect mitered corners.
When to Use This Calculator
- Frame Construction: Calculate miter angles for picture frames and window frames
- Polygon Frames: Determine miter angles for hexagons, octagons, and other polygons
- Corner Cuts: Calculate miter angles for any corner angle
- Saw Setup: Determine saw angle settings for miter cuts
- Educational Use: Learn and understand miter angle calculations
Why Use Our Calculator?
- ✅ Dual Calculation Modes: Supports corner-based and polygon-based calculations
- ✅ Accurate Formulas: Uses geometric equations for precise calculations
- ✅ Complete Analysis: Shows miter angle, corner angle, complementary angle, and sides
- ✅ Easy to Use: Simple inputs for corner angle or number of sides
- ✅ Time Savings: Instant calculations eliminate manual math
Understanding Miter Angles
Basic Principle: Miter angle is half the corner angle. For a square corner (90°), miter angle is 45°. For regular polygons, corner angle is calculated as 180 × (n-2) / n, where n is number of sides. Miter angle = Corner angle / 2.
Common Miter Angles: Square (90° corner) = 45° miter, Hexagon (120° corner) = 60° miter, Octagon (135° corner) = 67.5° miter, Pentagon (108° corner) = 54° miter. Different polygons require different miter angles.
Saw Setup: Set your miter saw to the calculated miter angle. Both pieces must be cut at the same miter angle for a perfect corner. For example, square corner requires both pieces cut at 45° miter angle.
Tips for Best Results
- Accurate Angle: Use precise corner angle or number of sides for accurate miter angle
- Verify Saw Calibration: Check that miter saw is calibrated correctly
- Test Cuts: Make test cuts on scrap material before final cuts
- Consistent Cuts: Cut all pieces at the same miter angle
- Check Corner: Verify corner angle matches desired angle
Frequently Asked Questions
How do I calculate miter angle?
Miter Angle = Corner Angle / 2. For example, 90° corner: Miter Angle = 90 / 2 = 45°. For polygons: Corner Angle = 180 × (n-2) / n, then Miter Angle = Corner Angle / 2. The calculator does this automatically from corner angle or number of sides.
What is the miter angle for a square frame?
Square frame (90° corner) requires 45° miter angle on each piece. Set saw to 45° and cut both pieces at 45° for a perfect square corner. Both pieces must be cut at the same miter angle.
What is the miter angle for a hexagon?
Hexagon (6 sides) has corner angle = 180 × (6-2) / 6 = 120°. Miter Angle = 120 / 2 = 60°. Set saw to 60° and cut all 6 pieces at 60° miter angle for a perfect hexagon frame.
Do I cut both pieces at the same miter angle?
Yes, both pieces must be cut at the same miter angle for a perfect corner. For example, square corner (90°) requires both pieces cut at 45° miter angle. Cutting both pieces at the same angle ensures the corner angles match correctly.
What if my corner isn't 90 degrees?
For any corner angle, miter angle = corner angle / 2. For example, 120° corner requires 60° miter angle, 135° corner requires 67.5° miter angle. Enter the actual corner angle in the calculator to get the correct miter angle.