Miter angle chart
The saw setting for a flat frame or ring of any number of sides, and for a corner that is not square. Every angle here is one cut on one end of one piece.
| Sides | Shape | Interior angle | Miter per end | Cuts in the job |
|---|---|---|---|---|
| 3 | Triangle | 60.0° | 60.0° | 6 |
| 4 | Square | 90.0° | 45.0° | 8 |
| 5 | Pentagon | 108.0° | 36.0° | 10 |
| 6 | Hexagon | 120.0° | 30.0° | 12 |
| 8 | Octagon | 135.0° | 22.5° | 16 |
| 10 | Decagon | 144.0° | 18.0° | 20 |
| 12 | Dodecagon | 150.0° | 15.0° | 24 |
| 16 | 16-sided | 157.5° | 11.3° | 32 |
| 24 | 24-sided | 165.0° | 7.5° | 48 |
Reading it
- The miter per end is 180 ÷ sides. A square frame is 45°, a hexagon 30°, an octagon 22.5°.
- This is the flat case — pieces lying in one plane. A ring whose staves lean inward is a compound miter and needs a bevel too; that is the segmented ring calculator.
- Error multiplies by twice the number of joints. A twelve-sided ring with every cut 0.1° over leaves 2.4° of the 360° unaccounted for, which is a visible gap.
- For a corner that is not one of these, the miter is (180 − the corner you measured) ÷ 2.
For the case this table does not cover
- Miter angle calculator
The miter for baseboard, casing or chair rail at any corner angle — flat trim, so there's no bevel to set.
- Segmented rings and columns
Miter and bevel for any number of sides, flat or flared, and how long each segment has to be.
- Picture frame miter cuts
Cut lengths, long point to long point, for a rectangular mitered frame, and how much molding to buy.