Picture frame
Picture Frame Miter Calculator
Cut both ends of every piece at this angle, alternating direction. All pieces must be the same length.
Quick answer
Miter angle = 180 ÷ number of sides. A rectangle is 45°, a hexagon 30°, an octagon 22.5°.
The two rules for tight frame corners
Frames live or die on two things: the angle and the lengths. The angle this calculator gives you is exact, so the bigger risk is length. Every piece sharing an edge length must be cut identically — use a stop block on your saw so each cut repeats to the thousandth. Then dry-fit the whole frame with a band clamp before any glue touches it. If one corner gaps, shave a hair off the mating pieces rather than chasing the angle.
FAQ
+What angle do you cut a picture frame?
A standard rectangular (4-sided) frame is cut at 45° on each end. For other shapes, divide 180 by the number of sides: a hexagon is 30°, an octagon is 22.5°.
+How do I cut a hexagon or octagon frame?
Set your miter saw to 30° for a 6-sided hexagon or 22.5° for an 8-sided octagon, and cut both ends of every piece at that angle with the pieces alternating direction. All pieces must be exactly the same length.
+Why won’t my frame corners close?
Two usual causes: the angle is slightly off, or the pieces are not identical lengths. Even a tiny length difference multiplies around the frame. Cut all pieces with a stop block so they match exactly, and test-fit before gluing.
+What is the formula for a polygon frame miter?
Miter angle per piece = 180 ÷ number of sides. That is the saw setting from the square detent. It works for any regular polygon frame.