Fence material formula
The fence run is reduced by the total gate opening before panel sections are counted. A straight run needs an end post at both ends; each gate splits the run and introduces another terminating post. The concrete calculation uses the actual cylindrical hole volume minus the volume occupied by the post.
Worked example: 100 ft privacy fence
For a 100 ft straight run with one 4 ft gate and 8 ft maximum spacing, the material run for panels is 96 ft. The page calculates the required sections, then counts the terminal posts created by the gate. Change the picket width, gap, rails per section, and hole geometry to match the fence you are actually building.
The post-count mistake this calculator avoids
“Length divided by spacing” gives you a number of spaces, not necessarily the final post count. A straight fence run needs one more post than its number of sections. Gates also split the run. Treating sections and posts as the same number is the common off-by-one error.
Concrete is calculated from geometry, not a generic bags-per-post rule
Instead of hard-coding “two bags per post,” Nioret Takeoff calculates the hole volume from your diameter and depth, subtracts the portion occupied by a square post, and divides by the bag yield you select. Product yields vary, so verify the value on the bag you are buying.
Reference note: The default 0.45 ft³ (60 lb) and 0.60 ft³ (80 lb) yields match the published QUIKRETE Concrete Mix No. 1101 technical data. Treat them as product examples, not universal bag yields. QUIKRETE technical data ↗
Fence calculator FAQ
Does the fence calculator include gates?
Yes. Enter the number of gates and width per gate. Gate openings are subtracted from the picket run and the post count is adjusted.
Can I use panels instead of individual pickets?
Use the section count as the starting point for panel quantity. Confirm the manufacturer's actual panel width and the layout around gates and corners.
How many bags of concrete per post?
There is no reliable universal number. Use the hole geometry and the actual bag yield. This calculator does that math for you.