Wood fence calculator

How to estimate a wood fence in five steps

1. Add your runs. Enter the length of each straight run in feet. Add the number of gates and the width of each one: a gate's width comes out of its run. Say whether the fence is open or a closed loop.
2. Set spacing, rails and pickets. Choose the post spacing (8 feet to start), the rails per section (2 or 3), the picket width and the gap between pickets. Sections, posts, rails and pickets show at once, with the waste percentage added to rails and pickets.
3. Size the post holes. Enter the hole diameter and depth in inches, the post width and the bag size. You get the concrete for one post, the total in cubic feet and the number of bags, rounded up.
4. Type your prices. We never show a price we did not source, so the price boxes start empty. Type what your supplier told you and a cost range appears. Bids can be compared per linear foot.
5. Print the sheet. Download a one-page sheet in English, Spanish or both to bring to your supplier or contractor.

What this calculator does, and what it does not

It turns the length of your fence into a shopping list: sections, posts, rails, pickets, and the concrete for the post holes. The counts are arithmetic on the numbers you type, so they come out the same every time you enter the same numbers.

It is an estimate, not a plan. It cannot see your soil, your slope or your gate hardware, and it does not say what your yard needs. Check your supplier's sizes before you buy, because a post, a rail or a picket may not be cut the way the page assumes.

Sections and posts

A section is the stretch of fence between two posts. The calculator divides the run by the post spacing and rounds up, because a last short section still needs its own post. An open run needs one more post than it has sections, since both ends need a post. A closed loop comes back to where it started, so it needs as many posts as sections.

Each gate adds a post in this estimate, and the gate's width is taken out of its run before the sections are counted. If you enter a 60 foot run with one 4 foot gate, the fence itself is 56 feet.

Worked example: a 100 foot run

Take one straight run of 100 feet, posts 8 feet apart, 3 rails per section, 5.5 inch pickets with no gap, 10 percent waste, a hole 12 inches across and 32 inches deep, a 3.5 inch post and 50 pound bags.

Sections: 100 divided by 8 is 12.5, which rounds up to 13. Posts: 13 plus 1 is 14. Rails: 13 sections times 3 is 39, and 10 percent waste makes it 43. Pickets: 1,200 inches divided by 5.5 is about 218.2, which rounds up to 219, and with waste it is 241. Concrete: 26.1456 cubic feet in all, which is 70 bags.

Pickets across a run

The run's length in inches is divided by the picket width plus the gap, and the answer is rounded up. Pickets set edge to edge use only the width. Pickets with a gap between them cover more distance each, so you need fewer of them.

A second example: a 50 foot run with 5.5 inch pickets and a 0.5 inch gap. Each picket takes 6 inches, so 600 inches needs 100 pickets, and with 10 percent waste you buy 110. Check your supplier's sizes, because a board sold as 6 inches wide is often narrower once it is cut.

Rails and waste

Rails are the horizontal pieces the pickets are fastened to. The calculator multiplies the sections by the rails per section, then adds the waste percentage and rounds up. Two rails per section is common for a short fence, and three adds a rail in the middle. This page does not say which one your fence needs.

Waste covers cut ends, boards that arrive bent or split, and mistakes. The default is 10 percent, and it applies to rails and pickets only: posts and concrete are not padded. You can change it. A fence with many angles or a lot of cutting may call for more.

Gates, corners and closed loops

Corners and gates are where this estimate is least certain. A corner may need extra posts or a different layout than a straight run. A gate usually needs sturdier posts, a latch and hinges, and the opening is not always the same as the gate. Each run you enter is rounded up on its own, so a fence with many runs can come out with a few more sections than one long run of the same total length.

Treat the post count as a starting point for a conversation. Show the sheet to a contractor or your supplier and ask how they would set the corners and the gate posts.

Concrete for post holes

The calculator treats each hole as a cylinder and subtracts the space the post takes up. In the 100 foot example, a 12 inch hole 32 inches deep with a 3.5 inch post leaves about 1.8675 cubic feet of concrete around each post. Times 14 posts, that is 26.1456 cubic feet. A 50 pound bag is taken as about 0.375 cubic feet, so 26.1456 divided by 0.375 is about 69.7, and the bags are rounded up to 70.

In the 50 foot example, 8 posts in 10 by 24 inch holes need 7.3655 cubic feet, which is 20 bags. The concrete figure ignores any gravel base, so it errs high. Bag yields differ, so check the label on the bag you plan to buy. You can pick 40, 50, 60 or 80 pound bags.

Where the hole size comes from

The starting hole size is a rule of thumb from a maker's instructions: a hole about three times the width of the post, and about a third of the post's length underground. It is a place to start, not an answer. This page does not say how deep your holes go, and it makes no claim about wind, frost or soil. Ask your supplier or a local contractor, and type the hole size they give you.

Before you build or dig

Rules about where a fence may go, how tall it may be, what it is allowed to look like and whether it needs a permit differ from place to place, and this page does not cover them. Check with your city or county, and look at the neighbors' records and your own survey papers if you have them. If you live in an association, ask them too.

Call 811 before you dig. It is the national number for having buried lines marked. Do it before the first post hole, not after.

• Ask the city whether a permit is needed.
• Ask for your lot's survey or plat records.
• Call 811 before any digging.
• Ask your supplier to confirm board and bag sizes.
• Ask a contractor how they would handle corners and gates.

Your answers and your privacy

The calculator runs in your browser. It has no place to type a phone number, an email or an address, nothing you enter is sent to a server, and nothing is saved when you close the page. Print the sheet if you want to keep the numbers.

Frequently asked questions