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Fence calculator

Enter the length, the height and the style of a wood fence. We space the posts, count the rails and pickets, size the post holes and count the concrete, the gravel and the fasteners.

A 100 ft fence 6 ft tall takes 16 posts (4x4 x 10 ft), 45 rails and 230 pickets, with 67 bags of fast-setting, 50 lb bags to set the posts.
Layout
14 bays, 3 rails each, posts 8 ft apart or less
Each post hole
10.5 in wide, 42 in deep: 6 in of gravel, then 3 ft of post
Concrete per post
3.8 bags of 50 lb (1.42 cu ft)
What to buy for the fence
ItemQty
4x4 x 10 ft pressure-treated post, ground contact16 posts
2x4 x 8 ft pressure-treated rail42 boards
2x4 x 8 ft pressure-treated, gate rails2 boards
2x4 x 8 ft pressure-treated, gate brace1 board
5 1/2 in dog-ear fence picket, 6 ft230 pickets
Quikrete 50 lb Fast-Setting Concrete Mix67 bags
Gravel for the hole bottoms, 0.5 cu ft bags11 bags
2 in galvanized ring shank nails for the pickets1,380 nails
3 in exterior screws for the rails168 screws
Gate hardware kit, hinges and latch1 kit

Pickets include 5% extra and cover the gates too. Concrete and gravel include 10% extra for uneven holes.

Price this list: fence cost calculator

The same list with dated store prices and a price box on every line.

Planning figures for a wood picket or privacy fence, not a permit drawing. Check your property line, your HOA and your town's fence rules on height and setback, and call 811 before you dig.

How the fence calculator works

Enter the total length of fence, gates included, the height and the style. The calculator takes the gate openings out of the length, divides what is left by the post spacing and rounds up to whole bays. Each corner starts a new run, so it adds a bay and a post, and each gate adds a post so the opening has one on both sides.

Posts

Every post is buried by the depth rule you pick, or to your frost depth if that is deeper, and stands as tall as the fence. The post length to buy is the next stock length up: a 6 ft fence on the 1/3 rule needs a 9 ft post, so you buy 10 ft posts. Corner, end and gate posts carry the most load; some builders use 6x6 posts there.

Rails

Each bay takes one 2x4 per rail row, cut to the post spacing. At 8 ft on center one 8 ft board spans a bay, which is why most wood fences use that spacing.

Pickets

The picket count covers the whole length, gates included, since each gate is faced with the same boards. Privacy boards butt edge to edge; shadowbox boards go on both faces and overlap by 1 in, which takes about 22% more boards; spaced pickets 3 1/2 in wide with a 2 1/2 in gap take one board every 6 in. A 4 ft picket fence 100 ft long is 210 pickets.

Concrete, gravel and fasteners

Each post sits on 6 in of gravel in a hole 3 times the post width, and the concrete fills the hole to 3 in below grade so soil and sod can go back on top. The calculator takes the post's own volume out before counting bags. Pickets take 2 galvanized ring shank nails or exterior screws at every rail, and each rail takes 4 3 in exterior screws into the posts.

Gates

A walk gate is framed with a 2x4 for each rail row and a diagonal brace that runs from the bottom on the hinge side up to the top on the latch side, so the gate cannot sag. Hang it on a gate hardware kit with two hinges and a latch, and leave about 1/2 in between the gate and each post.

Next steps

To set one post at a time, use the fence post depth calculator and the concrete for fence posts calculator. To price this list, use the fence cost calculator. Building a patio or a deck inside the fence? The paver calculator and the deck calculator count those.

Where the numbers come from

Post depth, hole size, the 6 in gravel base and the fill line come from Quikrete's instructions for setting posts in concrete; the frost depths by state and how they are worked out are on the fence post depth calculator. Bag yields are Quikrete's figures.

The layout is our own common-practice choice, not a code figure: posts at most 8 ft apart, 2 rails up to 4 ft, 3 rails up to 6 ft, 4 rails up to 8 ft, 2 fasteners per picket at each rail and 4 screws per rail, 5% extra pickets and 10% extra concrete and gravel. Change the spacing in the calculator if your fence maker says otherwise.

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Questions

Anything else? Write to us or see every calculator.

Questions people ask

Measure every run and add them up, gates included. Divide the length without the gates by the post spacing and round up to get the bays, add one post to start, one for each corner and one for each gate. Each bay takes one rail per rail row, and the pickets cover the whole length. A straight 100 ft privacy fence 6 ft tall with posts every 8 ft is 14 posts, 39 rails and 230 pickets.

With posts 8 ft apart, a straight 100 ft run has 13 bays and 14 posts. Each corner adds a post, and each gate adds one more because the gate needs a post on both sides. With 2 corners and one 4 ft gate, the same 100 ft takes 16 posts.

A 5.5 in dog-ear picket covers 5.5 in of fence, so 100 ft takes 219 pickets and 230 with 5% extra. A shadowbox fence, with boards on both faces overlapping 1 in, takes 281 for the same 100 ft. For 50 ft of privacy fence, 116; for 150 ft, 345.

Two rails up to 4 ft tall, three up to 6 ft and four up to 8 ft is the usual practice. A 6 ft privacy fence with posts every 8 ft takes three 2x4 x 8 ft rails per bay, 39 for a straight 100 ft run.

For 4x4 posts in holes 3 times the post width, set by the 1/3 rule on a 6 ft fence, each post takes about 3.8 bags of 50 lb fast-setting mix. The 14 posts of a 100 ft run need 59 bags with 10% extra. The concrete for fence posts calculator works it out for other holes and mixes.