Start with your own hole volume
The calculator does not assume a hole diameter, depth, or concrete bag size. Enter the volume for one post hole in cubic feet. The concrete result stays as an input prompt until that number is present.
total concrete volume = calculated posts × concrete volume per post
This keeps the material plan tied to the hole volume you intend to use for the particular fence run.
Read bag yield from the packaging
Enter the yield for one concrete bag in cubic feet from its packaging. The calculator divides total concrete volume by that yield and rounds up so the result is a whole number of bags.
concrete bags = ceil(total concrete volume ÷ bag yield)
If either local input is missing, the page shows an instruction instead of supplying a made-up quantity.
Why the post count matters
Concrete volume uses the post count already calculated for the single run. That count starts with the straight-run sections and includes one endpoint post, while every gate adds two gate posts in this calculator's planning method.
Use the bag count as a planning result
Review your entered hole volume and bag yield before relying on the result. The output is a transparent planning quantity for this tool, not an installation instruction or a replacement for product information and local requirements.