Hole Volume Calculator
Concrete needed to fill round post holes.
Estimate concrete to set fence or deck posts in round holes.
The math behind it
Each hole is a cylinder: π × radius² × depth; multiply by the number of holes.
Worked example
6 holes, 10 in across, 3 ft deep → ~9.8 ft³.
FAQ
Subtract the post?
For accuracy, subtract the post's buried volume; ignoring it adds a small safety margin.