Vinyl Fence Post Cap Size Options Explained
When you're shopping for a post cap, picking the right size is incredibly important to ensure your project goes smoothly. Depending on the type of post cap you get, purchasing enough for your fence line or railing can be a big investment. The last thing you want is to find out mid-install that the post caps don't fit on your posts, whether they are vinyl or wood. To make it easier on you, we've put together this guide that should put you on the right track for selecting the right size post cap.
How To Measure Your Post For A Post Cap
The way our post caps are labeled is designed to make the selection process easier. The post caps that we offer are named and categorized by the size of the post they are made to fit. For example, a 4” post cap may measure slightly different dimensions, but it will still work for a 4x4 post.
Material-Based Sizes - Measuring for Wood Posts
Always be sure to take the true measurement of your posts, especially if you are working with wood. Lumber sizes often use nominal dimensions, meaning the size it's labeled as differs from the actual true dimensions. For example, a 4 x 4 wooden post does not actually measure 4”. The real dimensions are 3 1/2" x 3 1/2".
Internal VS External Post Caps
Another thing to keep in mind when measuring is the technical design of the cap itself. Internal and external post caps fit differently in the post. An external cap fits on the outside of the post, while internal caps are made with tabs that slip on the inside of the post. Internal post caps are only used with vinyl posts.
Measuring an External Post Cap: Use a tape measure to find the dimensions from the outer edge of the post wall to the other outer edge of the post wall.
Measuring an Internal Post Cap: Use a tape measure to find the dimensions of the post from the inner wall to the opposite inner wall of the post.
Available Post Cap Sizes
We offer a wide range of post cap sizes, styles, and colors to ensure that you will find the right cap for your vinyl fence or railing. To make things a little easier, we've compiled all of our post cap sizes and the post size they are made to fit into the charts below.
External Post Cap Sizes
| Post Size (OD) | Cap Size (External) |
|---|---|
| 2" x 2" | 2" External Cap |
| 2 1/2" x 2 1/2" | 2 1/2" External Cap |
| 3" x 3" | 3" External Cap |
| 3 1/2" x 3 1/2" | 3 1/2" External Cap |
| 3 5/8" x 3 5/8" (4" Wood Post) | 3 5/8" External Cap |
| 4" x 4" | 4" External Cap |
| 4 1/4" x 4 1/4" | 4 1/4" External Cap |
| 4 1/2" x 4 1/2" | 4 1/2" External Cap |
| 4 1/2" x 4 1/2" (5" Wood Post) | 4 1/2" External Cap |
| 5" x 5" | 5" External Cap |
| 5 1/2" x 5 1/2" | 5 1/2" External Cap |
| 5 5/8" x 5 5/8" (6" Wood Post) | 5 5/8" External Cap |
| 6" x 6" | 6" External Cap |
| 6 1/2" x 6 1/2" | 6 1/2" External Cap |
| 8" x 8" | 8" External Cap |
Internal Post Cap Sizes
| Post Size (OD) | Cap Size (Internal) |
|---|---|
| 4" x 4" | 4" Internal Cap |
| 5" x 5" | 5" Internal Cap |
We hope you found this guide useful, but if you need some assistance in measuring your post cap or selecting the correct size cap, don't hesitate to give our expert sales team a call. We would be happy to assist you so that you are satisfied with your post-cap investment!
