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Privacy Fence Calculator

Three sides of a back yard — pickets edge to edge, rails behind, posts at the corners.

An estimate of material — your lumber yard's lengths and prices decide the order.

100' · 1200 in · 100 ft · 30.48 m

100 ft

5% covers pickets split by a screw or culled for warp and knots. It is added once, to the pickets — the posts, rails and concrete are counted from the fence itself.

This page recalculates as you type. There is no Calculate button.

Answer

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Pickets, with waste

230 pickets

100 ft of fence · 13 bays · 14 posts in holes 42" deep

Posts 14 posts
Rails 39 2×4s · 3 a bay
Fence, gates left out 100 ft
Concrete 47 × 50 lb fast-setting
Gravel under the posts 8 × 50 lb bags (0.5 ft³)
Ticked items cost $1,513.98
More numbers
Post holes 42" deep, 10" across
Widest post spacing 7' 8 5/16" on center
DrawingThe project drawn to scale. Run 1: 100' × 6'.100'6'Run 1

Buying noteCall 811 a few business days before you dig. It is the free national before-you-dig service: the utilities mark their lines, and every post hole needs it.
Buying noteYour frost depth is not set. Where the ground freezes, a post set above the frost line heaves: ask your building department for the depth (IRC Table R301.2(1)) and type it under Assumptions — every hole follows it.

Breakdown

Run or gate Measurements Qty Length Share
Run 1 100' Add ×1 100 ft

What to buy

Buying noteCall 811 a few business days before you dig. It is the free national before-you-dig service: the utilities mark their lines, and every post hole needs it.
Buying noteYour frost depth is not set. Where the ground freezes, a post set above the frost line heaves: ask your building department for the depth (IRC Table R301.2(1)) and type it under Assumptions — every hole follows it.

Ways to buy the concrete

The bags for every post hole together, by the shape of the holes. Every way is worked out; pick the one you will buy.

47 × 50 lb fast-setting Bags 47 Left over 0.17 ft³ Weight 2,350 lb Cost $375.06 Reference price $7.98. Type your store's.

Shopping list

14 14 × 10 ft $236.60 Reference price $1.69. Type your store's.
230 230 × 6 ft $524.40 Reference price $0.38. Type your store's.
39 39 × 8 ft $187.20 Reference price $0.60. Type your store's.
3 3 × 5 lb box (453) $113.91 Reference price $10.97. Type your store's. Reference price $37.97. Type your store's.
1 1 × 5 lb box (309) $32.97 Reference price $32.97. Type your store's.
14 14 × 4×4 caps $111.72 Reference price $7.98. Type your store's. Reference price $12.98. Type your store's.
47 47 × 50 lb fast-setting $375.06
8 8 × 50 lb bags (0.5 ft³) $43.84 Reference price $5.48. Type your store's.
Ticked items $1,513.98

Untick what you already have. Lumber is priced by the foot, beside its row; the concrete's bags are priced in the table above.

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How this was worked out

Every number below is yours. Each constant links to the row where you can change it.

Run 1 100' 100 ft
Posts 13 bays in 1 runs: 12 line + 2 end + 0 corner + 0 gate 14 posts

Change:Widest post spacing, wood

How deep a post goes 0.5 × 72" out of the ground, or the frost depth 0" where deeper 36" + 6" = 42"

Change:Post in the ground, share of its height aboveYour frost depthGravel in the bottom of a hole

Posts, length 72" + 36" = 108" 14 × 10 ft
Concrete, each post (π ÷ 4 × 10" × 10" − 3 1/2" × 3 1/2") × 32 1/2" 1.247 ft³ × 14 = 17.455 ft³

Change:Hole across, 4×4 postConcrete stops under the ground

Bags of concrete 17.455 ft³ ÷ 0.375 ft³ 46.55 → 47 × 50 lb fast-setting

Change:Yield, 50 lb fast-setting bag

Gravel under the posts π ÷ 4 × 10" × 10" × 6" × 14 3.818 ft³ → 8 × 50 lb bags (0.5 ft³)

Change:Gravel in the bottom of a hole

Rails 13 × 3 = 39 39 × 8 ft

Change:A rail every

Pickets, edge to edge 1200" ÷ 5 1/2" 219 × 6 ft

Change:Gap under the pickets

With the waste for culls 219 × (1 + 5%) 229.95 → 230
Screws 219 pickets × 3 rails × 2 + 39 boards × 2 ends × 2 1,314 + 156

Change:Screws where a picket crosses a railScrews at each end of a rail

What it comes to 14 × 10 ft × $1.69/ft + 230 × 6 ft × $0.38/ft + 39 × 8 ft × $0.60/ft + 3 × $37.97 + 1 × $32.97 + 47 × $7.98 + 8 × $5.48 $1,513.98

Assumptions

Every one of these is editable. Change one and the answer changes with it.

Assumption Value Confidence
Widest post spacing, woodPosts of a wood fence no more than 8 ft apart, center to center: the spacing Inch Calculator and Omni both work at, and the length of the 2×4 rail that spans a bay. ≈ in Trade convention
A rail everyOne rail for every 24 in of fence height, never fewer than a top and a bottom one: Inch Calculator's rule - three rails on a 6 ft fence, two up to 4 ft. ~ in Derived or single-supplier
Gap under the picketsPickets stop about 2 in above the ground so they do not wick water; Freedom's vinyl kit sets its panels about 2 in up, and 2 in is the most ISPSC 305.2.1 allows over grass or gravel. ≈ in Trade convention
Screws where a picket crosses a railTwo screws where each picket crosses a rail, the usual nailing of a privacy fence. ~ screws Derived or single-supplier
Screws at each end of a railTwo screws at each end of a rail or a gate board, into the post or the frame. ~ screws Derived or single-supplier
Post in the ground, share of its height aboveQuikrete Fast-Setting Concrete Mix spec sheet, section 5: a post hole one half as deep as the post stands above ground. Quikrete's Setting Posts sheet says the same as one third of the post's length, and so does Home Depot's chain link guide for its posts. ratio From a data sheet or an agency document
Your frost depthYour frost depth, from your building department (IRC Table R301.2(1) is filled in locally). 0 means not given: every hole is then as deep as the post's own rule. Typed in, no hole stops above it. ≈ in Trade convention
Gravel in the bottom of a holeQuikrete Setting Posts, step 2: 6 in of gravel or crushed stone in the bottom of the hole, for drainage. in From a data sheet or an agency document
Concrete stops under the groundQuikrete Setting Posts, steps 4 and 6: fill the hole to 3-4 in below the top, then finish with soil. The middle of the range. in From a data sheet or an agency document
Hole across, 4×4 postQuikrete Fast-Setting spec sheet, section 3: a 4 in post set in a 10 in hole. Its rule of three times the post would make 10½ in for a 4×4. in From a data sheet or an agency document
Hole across, 6×6 postA 6×6 gate post. Quikrete's three times the post would be 16½ in, a hole few dig for a fence; 12 in is an auger's size. ~ in Derived or single-supplier
Yield, 50 lb fast-setting bagQuikrete Fast-Setting Concrete Mix spec sheet. ft³/bag From a data sheet or an agency document

How many pickets a privacy fence takes

Count the pickets run by run, edge to edge. A back yard closed on three sides — a 50 foot side, a 100 foot back and another 50 foot side — is 600 + 1,200 + 600 inches of fence. At 5½ inches a 1×6 picket that is 110 + 219 + 110 = 439 pickets, each run rounded up on its own because the last picket of a run is ripped to fit and its offcut cannot turn a corner. With 5% for the ones that split, warp or have a knot through them: 461.

A 6 foot fence stands on three rails a bay. The posts may be no more than 8 feet apart, so the sides are 7 bays each and the back 13: 27 bays, 81 rails of 2×4, each an 8 foot board. The posts are 24 inside the runs, 2 at the corners and 2 at the house — 28, each a 10 foot 4×4 set 36 inches deep on 6 inches of gravel, with 94 bags of fast-setting concrete between them.

Pickets: width, length, gap

A 1×6 picket is 5½ inches wide when it is dressed, and that is the number that counts — a fence figured at 6 inches comes out about 8% short. A privacy fence butts them tight; a gap of even ¼ inch drops the 100 foot back from 219 to 209 pickets and shows daylight. A 6 foot fence uses 6 foot pickets set 2 inches off the ground so they do not wick water; at 8 feet the pickets are 8 feet long and the posts 12.

RunBaysRailsPickets
Left side, 50 ft721110
Back, 100 ft1339219
Right side, 50 ft721110

Screws

Two screws where every picket crosses a rail is 439 × 3 × 2 = 2,634 screws 2 inches long, and two at each end of every rail is another 324, 3 inches long. The list buys them in the boxes a store sells, the cheapest way to cover the count. The spare pickets are not counted: nothing is screwed to them.

Before you build

Call 811 before you dig, and ask your town how high a back-yard fence may be — many stop at 6 feet, and the IRC exempts only fences up to 7 feet from a permit. Put the good side out if your town asks for it. We are not connected with any maker, store or supplier named here.