How to use the polygon angle calculator
- Enter the number of sides in the regular polygon.
- Enter the finished outside edge length of one side.
- Use the miter setting at both ends, reversing the direction to make each frame piece.
The formula
Miter = 180° ÷ sides; interior angle = 180° − 360° ÷ sides
Worked example
A regular hexagonal frame has six sides, 30° miters, and 120° interior angles. Six 200 mm outside edges produce a 1200 mm perimeter.
Before you measure and cut
The length must refer to the same edge on every piece. Long-point and short-point lengths differ with stock width.
Irregular polygons do not have equal corner angles. Measure those corners and use the miter angle calculator individually.
Frequently asked questions
What is the miter for an octagon?
For eight sides, 180 ÷ 8 = 22.5° at each end.
Does this calculate the overall frame diameter?
No. It reports angles and perimeter from the entered side length.