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Picket Fence Calculator

A front-yard picket fence and its gate — the pickets, and the even gap to space them at.

An estimate of material — check your town's rules for a fence near the street.

100' · 1200 in · 100 ft · 30.48 m

100 ft

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

Answer

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Posts

14 posts

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

Posts 14 posts
Panels 13 panels
Fence, gates left out 100 ft
Concrete 38 × 50 lb fast-setting
Gravel under the posts 8 × 50 lb bags (0.5 ft³)
Ticked items cost $2,470.91
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.

38 × 50 lb fast-setting Bags 38 Left over 0.15 ft³ Weight 1,900 lb Cost $303.24 Reference price $7.98. Type your store's.

Shopping list

12 12 × 9 ft $515.16 Reference price $4.77. Type your store's.
2 2 × 9 ft $85.86 Reference price $4.77. Type your store's.
13 panels, 6 × 8 ft $1,430.13 Reference price $110.01. Type your store's.
14 caps $92.68 Reference price $6.62. Type your store's.
38 38 × 50 lb fast-setting $303.24
8 8 × 50 lb bags (0.5 ft³) $43.84 Reference price $5.48. Type your store's.
Ticked items $2,470.91

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:Post spacing, vinyl panels

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

Line posts, length 72" + 36" = 108" 12 × 9 ft
End posts, length 72" + 36" = 108" 2 × 9 ft
Concrete, each line post (π ÷ 4 × 10" × 10" − 5" × 5") × 32 1/2" 1.007 ft³ × 12 = 12.084 ft³

Change:Hole across, vinyl postConcrete stops under the ground

Concrete, each end post (π ÷ 4 × 10" × 10" − 5" × 5") × 32 1/2" 1.007 ft³ × 2 = 2.014 ft³

Change:Hole across, vinyl postConcrete stops under the ground

Bags of concrete 14.098 ft³ ÷ 0.375 ft³ 37.59 → 38 × 50 lb fast-setting

Change:Yield, 50 lb fast-setting bag

Gravel under the posts π ÷ 4 × 10" × 10" × 6" × 12 + π ÷ 4 × 10" × 10" × 6" × 2 3.818 ft³ → 8 × 50 lb bags (0.5 ft³)

Change:Gravel in the bottom of a hole

Panels one panel to each of the 13 bays, the last of a run cut to fit 13

Change:Post spacing, vinyl panels

What it comes to 12 × 9 ft × $4.77/ft + 2 × 9 ft × $4.77/ft + 13 × $110.01 + 14 × $6.62 + 38 × $7.98 + 8 × $5.48 $2,470.91

Assumptions

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

Assumption Value Confidence
Post spacing, vinyl panelsA 6×8 vinyl privacy panel (Veranda Linden) is 91 in wide between 5 in posts: 96 in on center. Freedom's kit instructions space posts at the panel's width plus the post's. ~ in 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, vinyl postFreedom vinyl fence kit instructions, p. 2: a 10 in hole for a 5×5 post. Veranda's instructions say the same. in From a data sheet or an agency document
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 picket fence takes

Pickets with a gap between them are counted as pickets and gaps: n pickets and one gap fewer fill a run, so the count is (run + gap) ÷ (picket + gap), rounded up. A front-yard fence of two 30 foot runs either side of a 4 foot walk gate, in 1×4 pickets 3½ inches wide with 2½ inch gaps, takes (360 + 2.5) ÷ (3.5 + 2.5) = 60.4, so 61 pickets a run, and 9 on the gate: 131 pickets, 138 with 5% for culls. On a fence 3½ feet high each is a 4 foot picket set 2 inches off the ground.

Rounded up, the pickets will not land on exactly 2½ inches. Spread 61 of them evenly along 30 feet and the gaps come to (360 − 61 × 3.5) ÷ 60 = 2 7/16" — the width to cut a spacer block to, so the last picket meets the post as square as the first.

Rails, posts and the gate

A fence this low carries two rails a bay, top and bottom. Each 30 foot run is 4 bays of 7' 6", so 16 rails of 2×4, and 10 posts: 6 inside the runs, one at each end, and the two gate posts — 6×6, because a gate swings on them. The posts go 21 inches into the ground on 6 inches of gravel, half of what stands above it. The gate is framed from the same boards: two rails and a brace from the bottom of the hinge side to the top of the latch side, two hinges, and a latch.

Spacing

The gap is the Gap between pickets under Assumptions: 2½ inches is the figure Omni's fence FAQ uses, Inch Calculator uses 2. Narrow it and the count rises, widen it and it falls; the even gap on the page follows.

Round a pool the gap is not a matter of taste. Where the tops of the rails are less than 45 inches apart, as they are on any fence this height, the International Swimming Pool and Spa Code puts the rails on the pool side and holds the gaps to 1¾ inches (section 305.2.5); choose A pool under Assumptions and the page checks it. We are not connected with any maker, store or supplier named here.