Everything you ever wanted to know about octagonal prisms. Whether you’re a student learning about polyhedrons for the first time, or a parent who needs a recap, by the time you get to the end of this webpage, you’ll be an expert.

**Octagonal Prism Definition**

An **octagonal prism** is a 3D object with two regular octagon caps and rectangular or square sides.

**Octagonal Prism Paper Model and Net**

Below is a free printable octagonal prism net. Please open the pdf file by clicking on the image below. Then you will be able to download the file in your browser. (If you are unable to see the PDF, you may need an updated version of **Adobe Acrobat Reader.**)

**Construction Tutorial**

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**Octagonal Prism Surface Area Formulas**

The surface area of a prism is equal to the sum of the areas of its faces. An octagonal prism is made up of 8 rectangle faces and 2 octagon faces.

If you happen to know **R **and **B**, then you’re all done. But what if you only know the length of a few sides of the octagonal prism? No problem. Let’s take a look.

Notice that the first and second formulas are actually the same, since:

**R =al**

**B=2ad**

Instead of **8R +2B**, we get: **8(al) + 2(2ad)** which is equal to the second formula: **8al+ 4ad**

**Octagonal Prism Volume Formulas**

Notice that the first and second formulas are actually the same, since:

**B=2ad**

Instead of **Bl**, we get: **(2ad)l** which is equal to the second formula: **2adl**

**Vertices, Faces, and Edges**

An octagonal prism has **16 vertices,** **10 faces**, and **24 edges**.

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