Omni calculator
Last updated:

Wood Fence Calculator

Table of contents

Talking about wooden fences: the elements of a wooden fenceHow to calculate the material for a wood fence: instructions for the wood fence calculatorMore than wooden fences: calculators and tools for your projectsFAQs

Use our wood fence calculator to run the math when planning a wood fence: insert all the parameters you know, and we will print you all the information you need to gather the materials and start the construction.
Keep reading this article to learn:

  • What are the elements of a wood fence;
  • How to calculate the material for a wood fence;
  • How to use our wooden fence calculator.

Talking about wooden fences: the elements of a wooden fence

A fence is built around a few key elements. The supporting elements are the posts. Usually, you should choose sturdy timber stakes, as they will hold the weight of each section of the fence. The section of the fence is, in turn, the basic repeating unit. In each section, you can fit a given number of pickets. The pickets don't have a structural function so you can choose the preferred material and thickness. In each section of the fence, you must place several rails, horizontal beams that support the pickets. Theoretically, you can put as many rails as you want, but two of them will usually do the job!

Now that you know the elements of a wooden fence, you can learn how to calculate how many of them you will need: in fact, you need to know more than just the pieces you need. Before building your fence, you need to define the relationships between them. Our wood fence calculator uses this information to help you build your fence, so it's better to learn how to place your pickets.

How to calculate the material for a wood fence: instructions for the wood fence calculator

We'll proceed in steps: first, we'll find the number of sections and then analyze what's going on in each section.

The first quantity you must define is the fence's length. Then, determine the distance between the center of each pair of posts. Dividing these numbers will return two fundamental quantities:

  • The number of posts; and
  • The number of sections.

To find the number of section, use the following operation:

nsections=lfencedpostsn_{\rm{sections}} = \left\lceil\frac{l_{\rm{fence}}}{d_{\rm{posts}}}\right\rceil


  • nsectionsn_{\rm{sections}} — The number of sections;
  • lfencel_{\rm{fence}} — The length of the fence; and
  • dpostsd_{\rm{posts}} —The distance between posts.

In this formula, we used the ceiling operation, which means that we round up the result of the division to the next integer: you don't want to have a gap at the end of your fence at the cost of having a slightly longer fence, or a somewhat shorter section.

To find the number of posts, you must add 11 to the number of sections:

nposts=nsections+1n_{\rm{posts}} = n_{\rm{sections}} +1

This is also the time to define the height of the fence. Once you choose the height of your liking, add about 50%50\% to the height to find the recommended height of the posts. As the essential structural element of a fence, they need to be safely anchored in the ground.

Move on: let's analyze each section. You want to fit a given number of pickets in each section, with a defined spacing between them. You can calculate a reasonable estimate of the needed number of pickets by dividing the fence's length by the sum of the width of each picket and the chosen distance. Once again, we'll use the ceiling operation.

npcikets=lfencespickets+wpicketsn_{\rm{pcikets}} = \left\lceil\frac{l_{\rm{fence}}}{s_{\rm{pickets}}+ w_{\rm{pickets}}}\right\rceil


  • spicketss_{\rm{pickets}} — The spacing between pickets; and
  • wpicketsw_{\rm{pickets}} — The width of each picket.

Notice that we don't consider the post's width in this calculation, as you may want to cover them with the pickets.

The last items you need to consider are the rails. To find the required number of rails, multiply the number of rails in each section by the number of sections:

nrails=nsections×rsn_{\rm{rails}} =n_{\rm{sections}} \times r_\mathrm{s}

where rsr_\mathrm{s} is the number of rails per section.

You are all set: let's learn how to use our wooden fence calculator!

How to use Omni's wood fence calculator

We need only some crucial information to crunch all the math for you. All you have to insert is the following:

  • The fence's length and height;
  • The height of the posts;
  • Spacing and width of the pickets and
  • The number of rails per section.

You've probably already chosen such parameters when planning your fence: now it's time to go to the hardware store!

🙋 We added a section where you can calculate the concrete footing for your posts: it's straightforward to use if you need it. Insert the parameters of your post, and find how much concrete you need for your fence!

More than wooden fences: calculators and tools for your projects

If wood is not your jam, you can try our other tools that can be useful for your projects. Try:


How do I calculate the number of posts for my fence?

To calculate the number of posts for your fence:

  1. Define the length of your fence.
  2. Define the spacing between posts.
  3. Divide the length of the fence by the spacing between posts, then round up to the closes integer.
  4. Add 1 to the result of the previous step (or one section of your fence will remain without an ending post!

How many 10 cm pickets with 2 cm spacing I need for a 2 m fence section?

You need pickets. To find this result, follow these easy steps:

  1. Sum the width of a picket and the spacing between pickets: 10 cm + 2 cm = 12 cm.
  2. Divide the length of the section by the result of the previous step: 200 cm/12 cm = 16.67.
  3. Round the result to the next integer to find a "safe" number of pickets, in this case, 17.

This is the number of pickets for each section of your fence. Multiply it by the number of sections to find the total number of pickets.

How do I choose the height of a wooden fence's post?

To choose the height of a wooden fence's post, always add about 50% of the fence's height. A third of the post will be buried in the ground, ensuring a sturdy hold against wind and damage. For example, if your fence is 1 meter tall, you should buy a 1.5 m tall post.

parts of a fence

Number and length of posts needed

Number of rails needed

Number of pickets needed

Concrete for post footing

To calculate the volume of the concrete, we need to know the volume of the post. Hence the need for the post's exact measurements.

Visit the cement calculator to determine how much cement, sand, gravel, water, or money you'll need for this concrete volume.

Check out 28 similar home and garden calculators 🏡
Air changes per hourAir conditioner BTUArch...25 more