Planning result
For a 150 ft straight fence run with 8 ft maximum spacing, plan 19 sections and 20 posts before gates. Using rough 10 inch diameter by 30 inch deep holes, plan about 51 80 lb concrete bags after waste.
Assumptions
| Fence length | 150 ft straight run with no gates included. |
|---|---|
| Post spacing | 8 ft maximum spacing. |
| Hole size | 10 inch diameter by 30 inch deep. |
| Bag yield | 0.6 cubic ft per 80 lb bag for planning. |
Calculation
| Step | Result | Formula |
|---|---|---|
| Sections | 19 sections | 150 / 8 rounded up |
| Posts | 20 posts | 19 sections + 1 |
| Concrete per post | 1.36 cubic ft | 10 inch diameter x 30 inch deep hole, rough |
| Total concrete | 27.2 cubic ft | 20 x 1.36 |
| 80 lb bags before waste | 46 bags | 27.2 / 0.6, rounded up |
| 80 lb bags with waste | 51 bags | 46 x 1.10, rounded up |
Corners and gates change the count
This example is a straight run. Corners, end posts, gate posts, and slope changes should be placed before line posts are counted.
Hole size is the big variable
A wider or deeper hole can increase concrete quickly. Soil, frost depth, fence height, and gate load can all affect hole requirements.
Next step
Use the linked calculator or planning hub to adjust dimensions, waste, coverage, depth, spacing, or product packaging for the real project.
Related guides
FAQ
How many posts for 150 feet of fence?
With 8 ft maximum spacing, this straight-run example uses 20 posts.
How many concrete bags for 20 fence posts?
With the rough hole size used here, plan about 51 80 lb bags after waste.
Do gate posts need more concrete?
Often yes. Gate posts may need larger holes or stronger posts than line posts.