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Equal mitre angle calculator
Find matching mitre cuts for a flat corner or a regular polygon frame.
A clear answer. Here’s how.
For an equal joint in flat stock, each cut is half the interior corner angle measured from the long edge. A mitre saw’s setting measured away from a square crosscut is (180° − interior angle)/2. A regular n-gon has interior angle 180° − 360°/n, giving a saw setting of 180°/n. Assumes two equal cuts, flat stock and no compound bevel.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Corner input
- Regular polygon side count
- Number of polygon sides
- 6
Example result
- Interior corner angle
- 120°
- Each cut angle from the long edge
- 60°
- Each saw setting away from square
- 30°
Two equal cuts in flat stock. No compound bevel or saw-capacity check.