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Fence Calculator

**How to use the fence calculator?**

This fence calculator will help you estimate how much fencing material you need to complete your privacy fence project.

A fence estimator is a simple tool that can be used by following these instructions.

To start, decide** how long your fence will be** and how much space you want between posts. The typical post space is 6 to 8 feet or 2 to 5 meters, depending on your preference. Next, put the fence length and the space between posts in the first section of the fence calculator. This will return the number of posts you should buy and the number of sections defined by the number of posts.

** What is the height of the fence?** In order to see the length of the posts you need to buy, you need to put in the height of the fence. That is important because at least ⅓ of every post should be buried in the ground and secured with concrete.

* How many horizontal rails do you need per section of fence?* Most fences use two rails per section, but the number may vary depending on the fence’s style. Once you know the number of rails per section, you can calculate the total number of rails you need to buy. A rail is the same length as a section.

To **find the total number of pickets**, input the width of a single picket and the spacing between the pickets into the third section of the fence calculator.

**Enter the following into the calculator**

A) The dimensions of the post

B) The number of posts

C) The dimensions of the hole

D) The dimensions of the post

E) The diameter of your post for cylindrical posts

F) The width and thickness of the post for cuboid posts

**Equations used in the fence calculator**

*If you want to know how we calculate the number of fencing materials you need, here is a list of the steps we took:*

- Number of posts = (fence length / post spacing) + 1 (round the result up)
- Number of sections = number of posts – 1
- Post length = fence height * 1.5
- Total number of rails = number of rails per section * number of sections
- Total number of pickets = fence length in inches / (picket width + picket spacing) (round the result up)
- Volume of concrete = (hole volume – post volume) * number of posts
- Cuboid post volume = post width * post thickness * height of the buried part of the post
- Cuboid hole volume = (3 * post width) * (3 * post thickness) * height of buried part of post inches
- Cylindrical post volume = post radius² * height of the buried part of post * π (radius = ½ of post diameter; the height of the buried post = ⅓ of the post length)
- Cylindrical hole volume = (3 * post radius)² * height of the buried part of the post in inches * π

**Using the fence estimator – example**

Let’s walk through an example to make estimating fencing materials easier to understand.

**Calculating Posts**

We want to build a fence that is 1,000 feet long, with 7 feet in between each post and a height of 10 feet.

We will calculate the number of posts and how long they should be:

-Number of posts = (1,000ft / 7ft) + 1 = 142.85 + 1 = 143.85

We need to round the number up, so the number of posts is 144. This gives us 143 sections.

-Post length = 10ft * 1.5 = 15ft

**Calculating Rails**

If we want our fence to have 4 rails per section, then the total number of rails we would need is:

-Number of rails = 4 * 143 = 572

**Calculating Pickets**

Now let’s move on to the pickets. Let’s say our fence will be built out of pickets that are 5 inches wide, with 1 inch of spacing.

As 1,000 feet equals 12,000 inches, the total number of pickets will be:

-Total number of pickets = 12,000in / (5in + 1in) = 12,000 / 6 = 2,000

**Calculating Concrete Volume**

We need to estimate how much concrete we will need to secure the posts to the ground.

If we were to use cuboid posts that are 5 inches wide and 4 inches thick, they would be perfect for our needs.

Remember to change the height of the post into inches for this calculation – 15 feet equals 180 inches. ⅓ should be buried in the ground, so the height of the buried part will be 60 inches.

First, we need to calculate the volume of the part of the post that’s underground. We can do this by using the cuboid post volume equation:

-Post volume = 5in * 4in * (1/3 * 180in) = 20in² * 60in = 1200in³

*Next, we need to find the volume of the hole:*

We calculate the volume of the cuboid hole by subtracting the volume of the cuboid from the total volume.

-Hole volume =(3 * 5in) * (3 * 4in) * 60in = 10,800in³

Now, all we need to do is subtract the post volume from the hole volume and multiply the result by the total number of posts.

-Total volume of concrete needed = (10,800in³ – 1200in³) * 144 = 1,382,400in³

Concrete is usually given in cubic yards, so we see that we will need 29.63 cubic yards of concrete.

We now know that we will need to buy the following materials in order to build a fence of 10 ft high by 1000 ft long fence.

- 144 15-feet-high posts,
- 572 rails,
- 2,000 pickets,
- and 29.63 cubic yards of concrete.

**Here are a few tips to help you when buying fencing materials:**

- Decide the purpose of the fence and the type of material that will best suit your needs.
- Consider the size of the fencing material and how much you will need.
- Check the quality of the fencing material before you buy it.

When building a fence yourself, always keep in mind that you may make mistakes.

- It is generally recommended to buy about 10% more fencing materials than you actually need, in case you need to correct a mistake.
- If your fence is perfect on the first try, the additional materials won’t go to waste – you will have them ready for any future repairs.