Fence Calculator

A gate is a hole, so it comes off first

A gate is a hole in the fence. Its opening comes off the length before anything is divided, so no picket and no rail is ordered across it. A gate leaf hangs on two posts, but one of them is the line or terminal post where the fence stops and is already counted: a sheet that adds two posts per gate over-orders. On the default sheet, 100 ft with one 4 ft opening is 96 ft of fence to build: 92 ft with 2 gates, 90 ft with one 10 ft double. Order across an opening and you buy pickets for a hole.

Corners divide the line before the spacing does

A corner ends a section whether the spacing likes it or not, so the corners split the line into straight runs first and each run is divided on its own. An open line with C corners has C + 1 runs, a line that closes on itself has C. That is why 48 ft with four corners lands on ten sections of 4.8 ft rather than six of 8 ft. Here 96 ft over 3 runs is 32 ft a run, 4 sections at the maximum, so 4 per run and 12 in all. A 200 ft perimeter with 4 corners and 1 gate closes into 4 runs, 28 sections, 29 posts. The short-run case: 48 ft with 4 corners is 10 sections of 4.8 ft, not 6 of 8.

The post spacing you type is a MAXIMUM. The sheet divides each run by it, rounds the number of sections up, and prints the spacing it actually lands on - which is what you will pull a tape to. No required spacing is printed here: that is your local code and your fence's own design.

Posts by type, and the one a gate does not add twice

A post count is not one number. This sheet prints 14 as 9 line, 2 terminal, 2 corner and 2 gate posts — and only 1 post was ADDED for the gate, because its second leaf post is the line post already standing where the fence stops. Close the line and the terminals go. An exact 96 ft straight run takes 13, against 14 for 100 ft: one more section to stay under the maximum.

Pickets, the pitch, and the board that gets ripped

Pickets are counted across the whole picketed length at a pitch of one board plus one gap, rounded up. The last board is rarely a whole one, so the sheet prints the width it has to be ripped by instead of pretending it fits. A 1x6 is 5-1/2 in milled and a 1x4 is 3-1/2 in, but your product carries its own width. At 5.5 in a board the default line takes 210 pickets and rips the last by 3 in; open a 2.5 in gap gives 144, a 3.5 in face 330. Rails follow the sections: 36 at 3 a section, 24 at 2. Pre-built panels are bought one per section: the sheet orders panels and stops ordering rails and pickets, because they came with the panel. Panels here: 12.

The concrete a post displaces

Concrete per hole is the cylinder less the post: pi times the hole radius squared times the depth, minus the post side squared times the depth. On the hole this sheet opens with - 10 in across, 24 in deep, a 3-1/2 in post - the post is 15.6 % of the cylinder, so skipping it over-orders by that much. That is 0.9207 cu ft a hole and 12.89 cu ft for 14 of them, 29 bags at the 0.45 cu ft QUIKRETE publishes for its 60 lb Concrete Mix No. 1101 bag. Its other four bag sizes are offered in the form.

What this sheet will not print

The hole depth is the depth YOU dig to. How deep a fence post must be set, the frost line, the height your fence may reach and how far it must sit from the line are in your local code, and they are linked rather than reproduced. No embedment fraction is printed on this page. No hardware, no post cap and no oversized gate post are counted. A deck is a surface and a fence is a line: for boards, joists and footings see the deck calculator, which counts neither pickets nor gates.

Net       =  run - gates x gate width
Runs      =  corners + 1,  or corners when the line closes
Sections  =  ceil( ( net / runs ) / spacing ) x runs
Spacing   =  ( net / runs ) / sections per run
Posts     =  sections + 1 (open line) + gates
Pickets   =  ceil( net x 12 / ( picket width + gap ) )
Concrete  =  ( pi x ( dia / 2 )^2 - side^2 ) x depth,  per hole

What this sheet does that the pages we read do not

Six results ranked when this sheet was audited; three returned too little text to read, so nothing is claimed about them either way. Of the three we could read, one counts spacing, rails and pickets but types no post and takes no gate; one types its terminal posts but has no spacing and no concrete; the third is six calculators by material with no combined sheet. A-302 puts posts BY TYPE, rails or panels, pickets, gates, concrete and bags in one takeoff, redraws both views from what you typed, switches to metric and exports a CSV.

Frequently asked

How much concrete per fence post?

The hole less the post standing in it. The one this sheet opens with — 10 in across, 24 in deep — is 1.0908 cu ft of cylinder, and a 3.5 in post fills 15.6 % of it: 0.9207 cu ft a hole, and your own hole size moves it.

What fence post spacing does this use?

Yours, as a maximum. 8 ft typed on a straight 100 ft line gives 13 sections of 7.692 ft; on an exact 96 ft it lands on 12 at 8 ft. No required spacing is printed here: that is your local code.

How much does it take to fence a yard?

A 150 ft lot fenced all the way round, 3 corners and one 3 ft gate: net 147 ft in 3 runs, 21 sections of 7 ft, 22 posts, 42 rails, 321 pickets and 46 bags of concrete. Quantities only: the price is the one you type, and none is invented here.

Limits of this sheet

A-302 counts material along the line you describe. It does not design a fence, check a property line or quote one, and chain link fittings are not counted. Your plans, your supplier and your local code govern.

Sheet A-302 prepared by TakeoffMetric Editorial; no author, credential or field measurement is claimed.