Miter Angle Calculator

Your details

Flat trim lies flat on the workpiece surface and needs only a miter angle. Crown molding sits at an angle to the wall and needs both a miter angle and a bevel tilt.
Inside corners are more common in rooms (walls meeting inward). Outside corners appear at bay windows and column wraps.
The angle of the corner as measured by an angle finder or protractor. A standard room corner is 90 degrees. A regular octagon corner is 135 degrees.
deg
When both pieces have the same face width the miter is simply half the corner angle. When widths differ (e.g. a narrow stile meeting a wide rail) the angles are unequal.
Miter angle
45deg

The horizontal rotation angle of the blade (board A, or both boards when widths are equal)

Saw scale setting (board A)45deg
Corner angle used90deg
45 deg
Shallow cut<22.5Standard22.5-45Steep cut45-67.5Very steep67.5+

For a standard right-angle corner, set the saw to 45.0 degrees.

  • Set your miter saw to 45.0 degrees. Cut both boards at the same angle, mirrored left-to-right.
  • For an inside corner, orient one board with the long point at the back face of the wood and the other with the long point at the front face.
  • Always sneak up on the final cut: make a test cut on scrap first and check the joint before cutting your finished material.

Next stepIf gaps appear at the joint, adjust by half the visible gap angle on each piece rather than correcting the full gap on one board.

 = Powered by OnlyCalculators