How many fence posts for 150 ft?
20 posts and 53 bags of concrete for a 150 ft fence line, at the settings most people start with. Below the calculator are the same numbers for the alternatives you are likely to choose, and what each one does to the total.
Reviewed · Method: measured dimensions, industry coverage rates, rounded up to real package sizes · How the numbers are calculated
Values are pre-filled for this page. Change anything and hit Recalculate.
The answer, and what it is made of
A 150 run at 8 ft centres needs 20 posts. That is the number of spaces plus one, which is the arithmetic most people get wrong — 150 ft divided by 8 is 19 spaces and therefore 20 posts. Setting them takes 31.4 cu ft of concrete, or 53 bags at 80 lb.
Planning figure for everything on that list: $957 to $2,528, with $1,544 as the realistic middle for the products most people actually buy. These are estimates for budgeting, not quotes. Prices move by region and by season, and the middle figure assumes a mid-range product rather than the cheapest thing on the shelf.
Spacing is a structural decision before a cost one: 16 posts becomes 20 posts when you close up from 10 ft spacing to 8 ft spacing. Wind load on the panels decides it, not the price of a post.
What changes if you change one thing
| Change the post spacing | You buy |
|---|---|
| 8 ft spacing, standard | 20 posts |
| 6 ft spacing, windy or privacy panels | 26 posts |
| 10 ft spacing, wire or field fence | 16 posts |
Every row is a live calculation, not an estimate. The shaded row is what this page defaults to.
What goes in the cart
| Item | Quantity |
|---|---|
| 4x4 posts, 8 ft | 20 pcs |
| Concrete mix, 80 lb bag | 53 bags |
| Rails or stringers, 8 ft | 57 pcs |
| Gravel for hole base | 20 buckets |
| Post level + line string | 1 set |
A third of the post goes in the ground. An 8 ft post in an 8 ft tall fence will not hold. Bury 30 to 36 inches, set the base in 4 inches of gravel so water drains away from the wood, and brace every corner post with a diagonal before the concrete sets.
What this size actually changes
One hundred and fifty feet at 8 ft centres is 18.75 spaces, which rounds up to 19 spaces and therefore 20 posts. That rounding is where the extra post comes from: dividing 150 by 8 gives 18.75, and 19 posts would leave a final gap of 6 ft and a fence with an odd panel at one end.
Figure. A post buried 30 in, in a hole about three times its thickness. Depth is what resists the panel load; the concrete only transfers it.
How the quantity is worked out
Post count is set by the spacing between posts, and the spacing is set by what the fence has to resist. A privacy fence with heavy panels needs posts at 6 to 8 ft. A wire or field fence can run 10 to 12 ft. The usual mistake is dividing the run by the spacing and forgetting the last post: a 150 ft run at 8 ft centres gives 19 spaces and therefore 20 posts, not 19.
Every post needs a footing, and the footing is the part that fails. The rule that matters is one third of the post length buried, and the hole should be roughly three times the post diameter. That is about 30 in deep and 10 in across for a 4x4, with concrete filling the hole and sloping away at the top so water runs off.
How to measure this job
Measure the fence line in a straight run where possible, and measure each straight segment separately when the fence turns. A run that steps around a corner needs a post at the corner and often a brace; a curved line needs shorter spacing than a straight one.
Then confirm the boundary before the first hole. Fence posts are the most common cause of neighbour disputes, and a fence built 6 in onto a neighbour's land can be ordered removed. Check the deed plan and, if it is unclear, agree the line in writing before digging.
Mistakes that cost real money
Dividing the length by the spacing and skipping the end post
A 150 ft run at 8 ft centres has 18 intermediate posts plus two end posts: 20 in total. Ordering 19 leaves you one post short, and the last panel cannot be hung. Always add one after dividing.
Setting posts by eye instead of by line
A string line pulled tight between the end posts, with every intermediate post checked against it, is the only way to get a straight fence. Posts set one at a time by eye produce a fence that looks drunk from thirty feet away.
Making the last panel a different width
If the run does not divide evenly, adjust the spacing of every panel slightly rather than leaving one short panel at the end. On 150 ft, spacing at 7 ft 10 in instead of 8 ft absorbs the difference invisibly across 19 panels.
Setting the end posts first and filling in by eye
Set both end posts, run a string line, then set intermediates against the line. Filling in from one end without a line produces a fence that curves by a few inches over 150 ft, which is obvious from the house.
Frequently asked questions
How many posts for 150 ft of fence?
Twenty at 8 ft centres, twenty-six at 6 ft. The count is the number of spaces plus one, so always round the spaces up and add the final post. Order one extra post — the last hole always turns out to be the one with a rock in it.
How many fence posts for 150 ft?
Twenty at 8 ft centres, twenty-six at 6 ft for a windy site or a privacy fence. The count is spaces plus one, and you should order one spare for the hole that hits a rock.
How many posts for a 150 ft fence?
Twenty at 8 ft spacing, 26 at 6 ft, 16 at 10 ft. Always round the number of spaces up and add one for the final post, then buy one spare.
How much concrete for 20 fence posts?
About 1.5 cubic feet per post for a 30 in deep, 10 in hole, so around 30 cubic feet in total: 53 bags of 80 lb, or a pallet and a half. Mixing that by hand is a long day; a mixer is worth hiring.
What will the materials for this cost?
A planning range of $957 to $2,528 for everything in the shopping list, with $1,544 as the realistic middle. That is materials only: it excludes labour, delivery, tool hire and disposal of the old surface. Treat it as a budgeting figure, not a quote.