Fence Post Calculator
Count fence posts from real layout geometry — total length, post spacing, corners and gates — then size the concrete per hole, total bags and weight, U.S. pricing, and a downloadable PDF.
Check your local code and frost line — hole depth and spacing rules vary. Prices use 2024-2025 U.S. figures. For planning purposes only.
| Spacing | Line Posts | Total Posts | Concrete Bags |
|---|
For your 150 ft fence. Wider spacing means fewer posts, but check that your panels or rails span the gap.
How to use the fence post calculator
Three quick steps turn a fence layout into an exact post count and a concrete order — line, corner, and gate posts, concrete per hole, total bags and weight, a spacing comparison, and a downloadable PDF.
Enter the layout
Total fence length, post spacing, fence height, and how many corners and gates.
Set posts & holes
Pick a post size, then set buried depth and hole diameter for the concrete math.
Choose concrete & price
Bag size sets the yield; add a price per post and per bag for the total.
Read it & save a PDF
Get post counts, bags and weight, a spacing comparison, and a download.
How the post & concrete count is calculated
Line posts come from the fence length and spacing; corners and gates add posts; then each post gets a concrete collar — the hole volume minus the post volume. Here is the exact math.
Worked example — 150 ft fence, 8 ft spacing, 4 corners, 1 gate, 4×4 posts in 10 in holes, 2 ft deep, 50 lb bags
Sections: ⌈150 ÷ 8⌉ = 19
Line posts: 19 + 1 = 20
Posts: (20 + 4 corners + 2 gate) × 1.05 ≈ 28
Hole: π × (10÷2÷12)² × 2 = 1.09 cu ft
Post: (3.5÷12)² × 2 = 0.17 cu ft → collar = 0.92 cu ft
Bags: ⌈0.92 ÷ 0.375⌉ = 3 per hole → 84 bags
28 posts, 84 bags (≈4,200 lb), roughly $924 for posts + concrete.
Wider spacing drops both the post count and the concrete order — but your rails or panels have to span the longer gap, so confirm they’re rated for it before you widen.
Post count, hole & concrete charts
Handy lookups for the questions people ask most — post types, post counts by length, hole and depth guides, concrete per hole, bag yields, and typical U.S. costs. Quantities start from the fence length, spacing, corners, and gates.
| Post | What it does | Rule of thumb |
|---|---|---|
| Line posts | Carry the run between corners | Length ÷ spacing, + 1 |
| Corner posts | Turn the fence, carry two directions | 1 per corner, set deeper |
| End / terminal posts | Close a run or meet the house | Counted in line + 1 |
| Gate posts | Hinge and latch a gate | 2 heavy posts per gate |
| Spare posts | Cover breakage and slope | ~5% of the total |
This calculator adds line, corner, and gate posts, then a spare allowance. Corner and gate posts usually step up to a heavier size and a deeper hole.
| Fence length | 6 ft OC | 8 ft OC | 10 ft OC |
|---|---|---|---|
| 50 ft | 10 | 8 | 6 |
| 100 ft | 18 | 14 | 11 |
| 150 ft | 26 | 20 | 16 |
| 200 ft | 35 | 26 | 21 |
Line posts = fence length divided by spacing, plus one to close the run. Add one post per corner and two per gate on top of these.
| Post size | Typical hole ⌀ | Common use |
|---|---|---|
| 4×4 wood (3.5 in) | 10–12 in | Line posts, most wood fences |
| 6×6 wood (5.5 in) | 14–16 in | Corner, gate, and tall posts |
| Round 4 in | 10–12 in | Wood or vinyl-sleeve posts |
| Metal 2⅜ in | 8 in | Chain-link line posts |
A hole about three times the post width is the usual target — wider grips better but takes more concrete. Terminal and gate posts run larger.
| Post · hole · depth | Cu ft | 50 lb | 60 lb | 80 lb |
|---|---|---|---|---|
| 4×4 · 10 in · 2 ft | 0.92 | 3 | 3 | 2 |
| 4×4 · 12 in · 2.5 ft | 1.75 | 5 | 4 | 3 |
| 4×4 · 12 in · 3 ft | 2.10 | 6 | 5 | 4 |
| 6×6 · 14 in · 2.5 ft | 2.15 | 6 | 5 | 4 |
| 6×6 · 16 in · 3 ft | 3.56 | 10 | 8 | 6 |
| Metal 2⅜ · 8 in · 2 ft | 0.64 | 2 | 2 | 2 |
Bags needed per hole, rounded up. Concrete per hole = the hole cylinder minus the post volume over the buried depth.
| Bag size | Yield | Bags for one 4×4 hole (0.92 cu ft) |
|---|---|---|
| 40 lb | 0.30 cu ft | 4 bags |
| 50 lb fast-set | 0.375 cu ft | 3 bags |
| 60 lb | 0.45 cu ft | 3 bags |
| 80 lb | 0.60 cu ft | 2 bags |
Bigger bags mean fewer to open but more weight to carry. Fast-setting 50 lb bags are popular for straight post sets — brace until cured.
| Item | Typical cost | Notes |
|---|---|---|
| 4×4 wood post | $8–$20 each | By length and grade |
| 6×6 wood post | $25–$45 each | Corner / gate duty |
| Metal line post | $10–$25 each | Chain-link |
| Concrete (bag) | $5–$8 each | ~2–3 per hole |
| Gravel (base) | $5–$8 / bag | A few inches per hole |
| Post setting, labor | $20–$60 / post | Dig, set, brace |
Planning ranges only. Prices swing with region, grade, and quantity, and corner and gate posts cost more than line posts.
Each post is a small load path into the ground: the visible post carries the fence, and a concrete collar in the hole locks it against wind and gate swing. The calculator counts posts, then sizes the concrete for every hole.
- Above grade — the visible post; fence height plus depth sets the length to buy.
- Buried depth — about a third of the post, always below the frost line.
- Concrete collar — fills the hole around the post; volume = hole minus post.
- Gravel base — a few inches under a wood post to drain water and slow rot.
Everything the calculator works out
One fence layout comes back as a complete post and concrete plan — every post counted, every hole filled, and the whole thing priced.
Key figures behind a fence post count
Built for anyone setting fence posts
From a short garden run to a full backyard enclosure, the same calculator turns a layout into an exact post count and a concrete order.
Setting a backyard fence and needs an exact post count and how much concrete to buy.
- Enter length, corners, gates
- Size the hole and depth
- Take the bag count to the store
Turning a layout into a post count, a concrete order, and a cost fast when quoting a job.
- Enter a known post count
- Compare spacings side by side
- Order posts, bags, and gravel
Weighing spacing, post size, and depth against the post and concrete bill.
- See posts by spacing
- Check bags and weight
- Save the PDF to shop quotes
7 tips for setting fence posts
Small habits keep your post count right and your fence standing straight, whether you’re setting a short run or a full enclosure.
Fence post calculator FAQ
The post-count, concrete, depth, hole, and spacing questions people ask most.
Post count starts with line posts — the fence length divided by the post spacing, plus one to close the run — then adds one post per corner and, if you frame gates, two posts per gate, plus a small spare allowance.
A 150 foot fence at 8 feet on center with 4 corners and one gate works out to about 20 line posts, 4 corner posts, and 2 gate posts, which lands near 28 posts after a 5% spare. This calculator counts each type and lets you edit the total.
Concrete per hole is the volume of the hole minus the volume of the post over the buried depth. For a 4×4 post in a 10 inch hole set 2 feet deep that’s about 0.9 cubic feet, which is roughly three 50 lb bags of fast-setting mix.
Bigger posts, wider holes, and deeper footings need more — a 6×6 in a 14 inch hole can take five or six bags. This calculator sizes the concrete per hole from your exact post, hole, and depth.
A common rule is to bury about one-third of the post’s total length, and always below your local frost line. Many codes call for roughly 24 to 48 inches of depth depending on climate.
For a 6 foot fence that’s often a 2 to 2.5 foot footing, so the post itself runs 8 to 9 feet. Corner and gate posts usually go deeper and wider because they carry the most load.
A good rule of thumb is a hole about three times the width of the post. A 3.5 inch 4×4 wants roughly a 10 to 12 inch hole; a 5.5 inch 6×6 wants about 14 to 16 inches.
A wider hole holds more concrete and grips better, but uses more bags. This calculator uses your hole diameter and post size to work out the concrete collar around each post.
It depends on the bag size and the hole. A standard 4×4 hole of about 0.9 cubic feet takes roughly four 40 lb bags, three 50 lb fast-set bags, three 60 lb bags, or two 80 lb bags.
Bigger bags mean fewer of them but more weight to carry. This calculator converts the concrete per hole into whole bags for the size you pick, then totals bags and weight for the whole fence.
Fence posts are usually set 6 to 8 feet on center. Six-foot spacing makes a stiffer fence and is common under tall privacy panels; 8 feet is standard for many wood fences and matches common rail lengths.
Wider spacing means fewer posts and less concrete, but your panels or rails have to span the gap. This calculator shows post and concrete counts side by side at 4, 6, 8, and 10 foot spacing.
Yes. Corner and gate posts carry more load than line posts, so they’re usually set deeper and in a wider hole, and often stepped up to a heavier post like a 6×6. Each gate is framed by two posts — a hinge post and a latch post.
This calculator adds one post per corner and two posts per gate on top of the line posts, so those extra holes and bags show up in the total.
For wood posts, a few inches of gravel at the bottom of the hole helps water drain away from the end grain, which slows rot and helps the post last longer. Set the post on the gravel, then pour the concrete collar around it.
Brace each post plumb until the concrete cures, and set corner and gate posts first. This calculator focuses on posts and concrete quantities, so confirm drainage and depth against local code.
General Estimating Notice: This calculator estimates fence posts and concrete — line, corner, and gate posts, concrete per hole, total bags and weight, and post and concrete cost — from your fence length, spacing, post size, hole diameter, and buried depth. Quantities are planning estimates and may differ from a surveyed layout. Post depth, hole size, and spacing must be confirmed against your local building code and frost line, along with property lines, setbacks, and utility locates before you dig. Concrete yields and prices use 2024–2025 U.S. figures and vary by region and brand. Call 811 and confirm code with a local pro — for planning purposes only.