Miter Angle Formula
Notes: For a standard 90-degree corner, the miter cut angle is 45 degrees.
Miter Angle Calculator — Miter Cuts for Any Corner
A miter joint is the most common joint in finishing carpentry. While 90° corners need a 45° miter, real walls are rarely perfectly square. This calculator gives the exact miter angle for any corner.
Formula
Miter Angle = Corner Angle / 2
Common Angles
| Corner | Miter Cut | Application |
|---|---|---|
| 45° | 22.5° | Octagonal frames |
| 90° | 45° | Standard corners |
| 120° | 60° | Hexagonal frames |
| 135° | 67.5° | Bay windows |
Frequently Asked Questions
How do I calculate a miter angle?
Divide the corner angle by 2. For 90°: 45°. For 135°: 67.5°.
Miter angle for a bay window?
Most bay windows are 135° (67.5° miter) or 120° (60° miter). Always measure the actual angle.
Why do miter joints have gaps?
Usually the wall is not exactly the assumed angle. Use a digital angle finder and adjust your saw accordingly.
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