Fence Calculator
This fence calculator turns a length into a full materials list. Enter how long the fence runs, set your post spacing and picket width, and you'll get the posts, sections, rails, pickets, and bags of concrete you'll need. Everything updates as you type, so you can try 6-foot versus 8-foot spacing in a second. It's free, you won't need an account, and it runs in your browser, so pricing a wood privacy fence or planning a weekend build takes no time. You'll see the list the moment you type.
- Posts and sections
- Rails
- Pickets
- Concrete bags
- Adjustable spacing
Last updated June 17, 2026 Feet and inches, straight runs Reviewed by the Calcowa team
Enter a fence length and a post spacing above zero.
Counts assume a straight run; add a post for each corner or gate. Standard pickets are 5.5 inches wide, and privacy fences use a zero gap.
How do you estimate fence materials?
A fence breaks into a few simple counts once you have the length. Divide the length by the post spacing and round up to get the sections, the gaps between posts, then add one post to cap the end, so a 100-foot fence at 8-foot spacing has 13 sections and 14 posts. Each section carries the rails you pick, usually 2 for a low fence or 3 for a 6-foot one, so the rails are the sections times that number. Pickets come from the length in inches divided by one picket width plus its gap, rounded up, which is why a tight 5.5-inch picket run needs more boards than a spaced one. Concrete is roughly a bag or two per post for setting them. You don't have to sketch it on paper, and you won't over-order or come up short, since it's all counted for you. This tool runs all of that, so it's quick to price a build or compare 6-foot and 8-foot spacing before you head to the yard.
Planning a fence, step by step
Here's the quick routine before you buy materials, and it's just four steps:
- 1
Measure the runGet the total length the fence will cover in feet.
- 2
Set the spacingPick 6 or 8 feet between posts; closer is sturdier.
- 3
Choose the picketsSet the picket width and any gap you want between boards.
- 4
Read the listYou'll get posts, rails, pickets, and concrete bags.
Posts by fence length
Here's the posts and sections for a straight run at 8-foot spacing, so it's easy to scan.
| Length | Sections | Posts |
|---|---|---|
| 50 ft | 7 | 8 |
| 100 ft | 13 | 14 |
| 150 ft | 19 | 20 |
| 200 ft | 25 | 26 |
Frequently asked questions
You give it the total fence length and a few choices, and it works out the materials. It divides the length by your post spacing to get the sections, adds one for the end post, multiplies sections by the rails each one needs, and figures the pickets from the picket width plus any gap. It also estimates the bags of concrete for setting the posts. It all runs in your browser, so you'll see the counts update as you change a number.
Most wood fences set posts 6 to 8 feet apart, with 8 feet being the common maximum for a sturdy line. Closer spacing, like 6 feet, makes a stiffer fence that handles wind and heavy panels better, while 8 feet uses fewer posts and costs less. The tool defaults to 8 feet, so drop it to 6 if your panels are heavy or your area gets strong gusts, and you'll see the post and rail counts update right away, so it's easy to compare.
Take the fence length in inches and divide by the width of one picket plus the gap you want between them. A 100-foot fence is 1,200 inches, so with 5.5-inch pickets set tight you need about 219, and adding a half-inch gap drops that to around 200. The calculator does that division and rounds up for you, so you'll order enough, and you can set the gap to zero for a solid privacy fence, which is what most folks build.
A fence usually runs 2 horizontal rails for a panel up to about 5 feet tall, and 3 rails for a 6-foot or taller fence to keep the pickets from warping. Each rail spans one section between posts, so the rail count is the number of sections times the rails per section. Pick 2 or 3 in the tool based on your fence height, and it multiplies that across every section.
A common rule is one to two 50-pound bags of premixed concrete per post, depending on the post size and how deep you set it, which is usually about a third of the post height. This calculator uses two bags per post as a solid default, so adjust it down for light posts in firm soil or up for tall posts and loose ground. The hole should be about three times the post width across.
Yes, it's completely free, with no sign-up, and it runs right in your browser, so nothing you enter leaves your device. Type your fence length, set the spacing and picket size, and read the full materials list in a tap. Bookmark it for planning a wood privacy fence, pricing a project, or a weekend build, and you'll have an accurate count of posts, rails, pickets, and concrete whenever you need it.
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