EstimatorKitFree fence take-off
Fence posts, rails and bags, counted side by side
Enter each straight side of the run and this returns the posts to set, the rails and pickets between them, and the concrete every hole takes in whole 40, 60 and 80 lb bags. The count worth getting right is the posts: a straight run needs one more post than it has bays, a run that closes on itself needs exactly as many, and every gate cut into either adds one. Hole depth follows the fence rather than a default — a third of the height above grade, or below your local frost line, whichever is deeper — which is also what decides whether a 6 ft fence is built from 8 ft posts or 10 ft ones.
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- Whole bags per hole
- Frost depth in the set
- Gates deducted
One row per straight length. Corners have to land on a post, so each side is divided into its own whole number of bays instead of the total being divided once.
8 ft is the usual ceiling because rail stock is cut in even lengths from 8 ft up, and a bay wider than the stick has to be spliced over a post. Every side is then divided down to a bay no wider than this, so the bays come out even rather than leaving a stub at the end.
Boards fixed to horizontal rails — spaced pickets, board-on-board, or butted for privacy. Set the gap to zero for a solid fence.
They are separate choices because they do separate work. A line post is held straight by the panel either side of it; an end, a corner and a gate post are pulled on from one side only, which is why they go up a size and end, corner and gate posts take the pull of a whole run rather than the panel either side of them, so they are set deeper.
Left blank, both follow an auger sized three times the post: 10 in for a 4×4, 16 in for a 6×6. Override them with the auger you can actually rent — the diameter moves the concrete faster than anything else on this page, because it is squared.
Posts to set
14 posts
12 bays, 1 gate opening, and one more post than bays, because the last bay still needs an end. Each gate ends one stretch of fence and starts another, so it brings a post of its own.
- Line posts, 4×4 timber
- 9
- End, corner and gate posts
- 5
- Total run
- 100 ft
- Fence between the gates
- 95.9 ft
- Widest bay
- 8'
The 5 terminals are counted as the most it can be: a gate hung off a corner post is doing both jobs with one post rather than two.
| Side | Length | Gates | Bays | Bay width |
|---|---|---|---|---|
| Side 1 | 60 ft | 1 | 7 | 7' 11 7/8" |
| Side 2 | 40 ft | 0 | 5 | 8' |
Set 24 in deep, so the posts are 8' long
A third of the 72 in standing above ground governs here — deeper than the frost depth you entered, so that is the number the holes are dug to. Terminal posts go 6 in deeper again, at 30 in.
- Line post length
- 8' — buy 8 ft
- Terminal post length
- 8' 6" — buy 10 ft
- Offcut per line post
- 0'
That leaves 0" spare on a 8 ft post. Posts are stocked in even feet, so a set depth that creeps a few inches deeper does not shorten the fence — it moves the whole order up to the next length, which is the line nobody prices.
| Bag | Bags | Per line hole | To lift | Spare |
|---|---|---|---|---|
| 40 lb | 85 | 3.44 | 3,400 lb | 0.27 cu ft |
| 60 lb | 57 | 2.29 | 3,420 lb | 0.42 cu ft |
| 80 lb | 43 | 1.72 | 3,440 lb | 0.57 cu ft |
25.2 cu ft of concrete and 9 bags of stone
- Line hole, 10.5 in across
- 1.03 cu ft
- Terminal hole, 16.5 in across
- 3.19 cu ft
- All holes together
- 0.93 cu yd
- Drainage stone, 4 in deep
- 4.28 cu ft
43 eighty-pound bags, 3,440 lb through the checkout. At this size nobody would consider a truck, which is the normal state of affairs for post holes.
| Stock | Rails a board | Boards | Left over |
|---|---|---|---|
| 8 ft | 1 | 41 | 11.5 ft |
| 10 ft | 1 | 41 | 93.5 ft |
| 12 ft | 1 | 41 | 175 ft |
| 14 ft | 1 | 41 | 257 ft |
| 16 ft | 2 | 21 | 19.5 ft |
232 pickets at 5 1/2", bare count 210
5 1/2" of board plus 0" of gap repeats every 5 1/2", so 95.9 ft of fence takes 210 boards before the 10% allowance. The remainder is wider than a gap, so the run closes on one more board ripped down to 1 1/2".
Butted tight, those boards will not stay butted: softwood moves about 4% across the face between the moisture content it is pressure-treated at and the one it settles to, which is 1/4 in on a 5 1/2 in board. A solid fence built from wet treated stock opens up to about 1/4" a joint by its second summer, which is the argument for board-on-board rather than for squeezing them harder.
Fasteners: 1392 into the pickets at 2 a crossing, 160 into the rail ends.
1 gate, 3 hinges, 1 latch
Each opening is 4.08 ft between post faces — the leaf plus half an inch at the hinge and half at the latch — the swing clearance a gate needs between its two posts. At this size the leaf gets three hinges: two carry it and the third stops the top corner dropping, which is what makes a gate stop latching.
Set depth is the fencing rule of thumb: a third of what stands above ground goes below it, so a 6 ft fence is set 24 in, taken against the frost depth you entered and the deeper of the two used. It varies with soil and exposure — a solid privacy fence in sand is a sail on a spike and wants more than a picket fence in clay. Hole diameter follows an auger sized three times the post: 10 in for a 4×4, 16 in for a 6×6. Concrete per hole is the auger circle less the section of post standing in it, over the depth the concrete occupies — the same arithmetic the concrete calculator uses — and bag yields are the ones printed on the bags: 0.6 cu ft from an 80, 0.45 from a 60, 0.3 from a 40. Stone is bagged at 0.5 cu ft: the common 50 lb retail bag of gravel or sand. Post sizes are PS 20 surfaced dry depth of a nominal 2×4.
How to take off a fence from a tape measure
Three things decide the whole order: where the sides break, how tall it is, and how far down the posts go.
Enter every straight side separately, and put each gate on the side it swings in
A corner has to land on a post, so each side is divided into its own whole number of bays rather than the total being divided once — a 60 ft side and a 40 ft side are not the same as 100 ft of fence. Tick the box when the last side meets the first, because a run that closes on itself needs one fewer post than an open one and that single post is the number most hand estimates miss. Each gate takes its leaf width plus swing clearance out of the run and puts a post of its own back in.
Give it the height above grade and the widest bay you will accept
The height drives two things at once: how many rails a bay needs, and how deep the posts go. Eight feet is the usual ceiling on a bay because rail stock starts at 8 ft and a wider bay has to be spliced over a post. Whatever maximum you set, each side is divided down until every bay is under it, so a 60 ft side at an 8 ft ceiling comes out as eight bays of 7 ft 6 in rather than seven of 8 ft and a 4 ft stub at the end.
Enter your frost depth, pick the post, and read the order
Set depth is the deeper of a third of the height above grade and the frost figure your building department publishes — zero where the ground does not freeze. That number decides the post length as well as the concrete, which is why a 6 ft fence is an 8 ft post in Georgia and a 10 ft post in Minnesota. The panel then gives posts split into line and terminal, rails against each stock length, pickets with the closing rip, and the concrete as whole bags. Copy hands over the whole take-off as plain text.
Technical specifications
| Post count | Bays plus one on a run with two ends, bays exactly on a run that closes on itself, and one more for every gate — a gate ends one stretch of fence and starts the next |
|---|---|
| Set depth | The deeper of a third of the height above grade and the frost depth you enter; end, corner and gate posts go 6 in deeper again |
| Hole diameter | Three times the post by default — 10 1/2 in for a 4×4, 16 1/2 in for a 6×6 — and editable, because the diameter enters the volume squared |
| Concrete per hole | The auger circle less the section of post standing in it, over the depth the concrete occupies: 1.03 cu ft for a 4×4 in a 10 1/2 in hole set 24 in, which is 2 eighty-pound bags |
| Bay division | Each side divided on its own: a 60 ft side at an 8 ft maximum is 8 bays of 7 ft 6 in, never 7 of 8 ft and a 4 ft stub |
| Rails per bay | Two to 4 ft, three to 6 ft, four to 8 ft — one fixing every 24 in of picket length — and overridable with your own number |
| Picket pitch | Face width plus gap: 100 ft of butted 5 1/2 in boards is 219 pickets and a 1 in rip to close the run |
| Data kept | None — the side lengths, gate widths and the frost depth for your address are multiplied in this tab and gone on reload |
Frequently asked questions
How many posts do I need for a 100 foot fence?
Fourteen if it runs in a straight line: thirteen bays of 7 ft 8 in and one more post to close the last one. That extra post is the whole trap — bays are the gaps between posts, so the posts always outnumber them by one on a run with two ends. Take the same 100 ft around a yard so the last side meets the first and it drops to thirteen, because the final bay ends on the post the first one started from. Add a gate and it goes back up: the fence stops at the hinge post and starts again at the latch post, so a gate carries a post of its own on top of whatever the bays need — though because the opening also comes out of the run, a wide enough gate takes a bay back out again.
How deep should a fence post be set?
A third of the height standing above grade, or below the local frost line, whichever is deeper. A 6 ft fence is a 24 in set by the first rule, and that is enough anywhere the ground does not freeze. Where it does, the bottom of the concrete has to sit below the depth the frost reaches or the plug is lifted a little every winter and never goes all the way back down — after five seasons the run has a wave in it that no amount of racking fixes. The published frost depth is a jurisdiction number, not a national one: the Gulf coast sets zero, northern-plains and interior New England counties set 48 to 60 in, and your building department is the only place the figure for your address exists.
Does the frost line change how long the posts have to be?
Yes, and it is the line that gets missed on the order. Post length is the height above grade plus the set depth, and lumber comes in even feet: a 6 ft fence set 24 in is exactly an 8 ft post, but the same fence in a county with a 42 in frost depth is a 9 ft 6 in post, which means buying 10 ft stock and cutting six inches off every one. That is a different price per post and often a different aisle, and someone who priced 8 ft posts before checking the frost depth is short by the whole difference. The tool shows the post length and the stock length it rounds up to for exactly this reason.
Why do the corner and gate posts take so much more concrete than the line posts?
Because both of the numbers that decide the volume go up at once, and one of them is squared. A line post is held straight by the fence on either side of it; an end, a corner and a gate post are pulled on from one side only, so they go up a size, get a wider hole and are set deeper. Move from a 4×4 in a 10 1/2 in hole set 24 in to a 6×6 in a 16 1/2 in hole set 30 in and the concrete goes from about 1 cubic foot to about 3.2 — three times as much, from what looks like a modest change. The hole diameter is the lever worth watching on any of these: it enters the volume as a square, so two inches wider costs more than four inches deeper.
Do fence posts have to be set in concrete at all?
Not all of them, and the argument is about water rather than strength. Compacted gravel around a post drains, so the wood stays wetter for hours rather than weeks and the post can be pulled and replaced with a bar instead of a jackhammer; concrete holds a post rigid but also holds a ring of water against it unless the hole is belled wider at the bottom and the top is crowned to shed rain. The usual compromise is what this page assumes: gravel under the post so its end is never standing in water, concrete around it from there to grade, and the collar sloped away. Where concrete earns its keep without argument is the terminal posts, which carry the gate and the pull of the whole run.
How many pickets does a 6 foot privacy fence take?
About 219 boards for 100 feet of run, using 5 1/2 in pickets butted tight, with the last one ripped down to an inch to close. The arithmetic is a pitch: the face width plus the gap repeats along the run, so 1,200 inches divided by 5 1/2 rounds up to 219 and the remainder is the rip. The part that surprises people comes later — pressure-treated stock is sold wet, and softwood moves about 4% across the face between the moisture content it is treated at and the one it settles to, which is a quarter inch on a 5 1/2 in board. A fence built butted tight in June has quarter-inch gaps through it by the following summer, which is the real reason board-on-board exists.
Why is 8 feet the usual maximum for a bay?
Because rail stock starts at 8 ft and a bay wider than the stick has to be spliced over a post. Everything else follows from that: pickets are cross-grain over the rail so the rail carries the whole panel, and a longer rail sags at the middle under its own load and the pickets on it. What the tool does with your maximum is divide each side down until every bay is under it, which is not the same as laying out 8 ft bays and leaving whatever is left at the end. A 4 ft stub bay at the corner is weaker than the bays either side of it, obvious from the street, and the offcut is wasted anyway.
About post counts, set depth and the two things that go wrong
Almost every fence estimate that comes up short does so in the same place, and it is not the lumber — it is one post. Bays are the gaps between posts, so a run with two ends always carries one more post than it has bays: 100 feet at an 8 foot maximum is thirteen bays and fourteen posts, and the fourteenth is the one nobody counts because it holds nothing up on its right-hand side. The rule flips on a run that closes on itself, where the last bay finishes on the post the first one started from and the count is exactly the bay count. Gates put the post back: the fence stops at the hinge post and starts again at the latch post, so cutting a gate into a run adds one post to the total wherever it sits. The other half of the same problem is the corners. A corner has to land on a post, which means each side has to divide into a whole number of bays on its own — dividing the whole perimeter once and laying out 8 foot bays from one end leaves a stub at every corner, weaker than the bays around it and visible from the street.
The second thing that goes wrong is underground, and it costs more than a post does. The trade rule is that a third of what stands above grade goes below it, so a 6 foot fence is set 24 inches — and that is right until the ground freezes. Where it does, the bottom of the concrete has to sit below the depth frost reaches, because a plug of concrete with freezing soil under it gets lifted a little each winter and does not come all the way back down; five seasons of that is a wave in the fence line that racking will not take out. The frost figure is local: the Gulf coast publishes zero, northern-plains and interior New England counties publish 48 to 60 inches, and only your building department has the number for your address. It changes more than the digging. Post length is the height plus the set, and posts are stocked in even feet — a 6 foot fence set 24 inches is an 8 foot post exactly, while the same fence over a 42 inch frost line needs 10 foot stock with six inches cut off every one. That is the line that turns a priced job into an unpriced one. The concrete itself is the arithmetic the concrete calculator uses for a post hole and this page reuses unchanged — the auger circle less the section of post standing in it, over the depth the concrete occupies — so the two agree to the bag. Post holes are also the one pour where the usual bag-against-truck crossover does not apply: forty holes is more than a cubic yard and still bags, because a ready-mix drum stiffens long before forty posts are plumbed and braced.
Two things about the infill are worth knowing before the order goes in. Pressure-treated pickets are sold wet, and softwood moves about 4% across its face between the moisture content it is treated at and the one it settles to — a quarter inch on a 5 1/2 inch board. A privacy fence butted tight in June has quarter-inch gaps through it the following summer, which is why board-on-board exists and why the gap on this page is a field rather than a default. Rails, meanwhile, are the reason bays stop at 8 feet: stock starts there, and a bay wider than the stick has to be spliced over a post. And if the fence is going around water, the height and the gate are not a taste decision. A pool barrier is specified — a minimum height, a self-closing and self-latching gate that swings away from the water, and no opening a small sphere passes through — with the exact figures set by the code edition your jurisdiction has adopted, so check it before the posts go in rather than after. The water inside the fence is measured on the pool volume calculator, and the bed that usually ends up running along the new fence line is priced by the mulch calculator.
Where the run you measured goes
Every number on this page is worked out by JavaScript running in the tab you are reading it in. Nothing you type — measurements, quantities, the prices your supplier quoted you — is uploaded, logged or kept, which is also why the calculators carry on working on a site with no signal.
The frost depth is the one entry worth calling out, because it is a fact about where you live rather than about your fence. It is used to pick a hole depth, it is compared against a third of the height, and then it goes the way of everything else on the page — nothing is sent anywhere, and reloading the tab clears it.