If you build a lot of tables or boxes, or really any project, that have varying numbers of sides, I’m certain you’ve repeatedly done the math to calculate the right miter angles for each of the scenarios. Below are quick reference images for the correct miter angles for objects with 3 sides up to 10 sides. Bookmark this page for a quick refence in the future.

3 Sides: The triangle

For a triangle, you’re miters will need to 60° off square. Sharp angles like these are tricky to cut on a miter saw. Build yourself a jig and save your fingers.

4 sides: The square

For a square, you’re miters will need to be 45° off square.

5 sides: The pentagon

For a pentagon, you’re miters will need to be 36° off square.

6 sides: The hexagon

For a hexagon, you’re miters will need to be 30° off square.

7 sides: The heptagon (or septagon)

For a heptagon, you’re miters will need to be 25.7° off square. This is where you start getting into the realm of trial and error. Make certain you test out your angle on some scrap wood first, since your miter saw most likely doesn’t have a specific stop for a 25.7° angle.

8 sides: The octagon

For a octagon, you’re miters will need to be 22.5° off square. Luckily, most decent miter saws do have a specific stop called out for a 22.5° miter.

9 sides: The nonagon (or enneagon)

For a nonagon, you’re miters will need to be 20° off square.

10 sides: The decagon

For a decagon, you’re miters will need to be 18° off square.

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