Free tool · Cutting & sheet goods
Miter Angle Calculator
Get the miter angle for any corner from its angle, or for a multi-sided frame from its number of sides. Each piece is cut at half the joint.
Regular frame reference
| Sides | Corner angle | Saw setting |
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Set your saw to the miter setting, and cut both mating pieces at that angle. A butt joint and a mitered joint share the same miter setting, the miter just adds a bevel for compound (sloped) work.
Miter Angle Calculator, explained
How do you calculate a miter angle?
Two pieces meeting at a corner each get cut at half the turn. For a square 90 degree corner that is a 45 degree miter on each piece. For any corner angle, the miter on each piece is (180 - corner angle) / 2. So a 135 degree corner takes a 22.5 degree miter, and a sharp 60 degree corner takes a 60 degree miter.
For a closed frame with equal sides, the miter on each end is simply 180 divided by the number of sides. A four-sided frame is 45 degrees, a six-sided (hexagon) frame is 30 degrees, and an eight-sided (octagon) frame is 22.5 degrees. This calculator does both: enter a corner angle, or enter the number of sides.
How it works
How the Miter Angle Calculator works.
By corner: Miter = (180 - corner angle) / 2 | By frame: Miter = 180 / number of sides - Choose how you are working: from a single corner angle, or from the number of sides in a frame.
- For a corner, enter the corner angle (90 for a square corner). For a frame, enter the number of equal sides.
- Read the miter angle to set on your saw for each piece.
- Cut both mating pieces at that angle so the joint closes cleanly.
Example: a square picture frame has 4 sides, so each end is mitered at 180 / 4 = 45 degrees. A hexagon planter has 6 sides, so each end is 180 / 6 = 30 degrees.
Miter Angle Calculator FAQ
Miter Angle Calculatorquestions.
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What miter angle is a 90 degree corner?
45 degrees on each piece. Two 45 degree miters meet to close a 90 degree corner. The rule is miter = (180 - corner) / 2, so (180 - 90) / 2 = 45.
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What is the miter angle for a hexagon?
30 degrees. A hexagon has 6 sides, and the miter for a regular frame is 180 divided by the number of sides, so 180 / 6 = 30 degrees on each end.
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How do I miter an odd-angled corner?
Measure the corner angle with a bevel gauge or angle finder, then cut each piece at (180 - corner angle) / 2. For example a 100 degree corner needs a 40 degree miter on each piece.
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