Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Masonry & Concrete
Post Hole Concrete Bag Calculator
Cu ft per hole = π × (d/2)² × depth; bags = total cu ft ÷ bag yield.
Bags of concrete for cylindrical post holes. Planning estimates only — verify measurements and local codes on site.
Inputs
1100
624
1248
0.41
220
Smart analysis
Recommendations
Tailored to your live inputs and result—guidance only, not professional advice.
- Interpret
Treat this as a planning estimate
Primary result: Concrete bags = 17. Re-run with optimistic and pessimistic inputs to understand the range—not just a single point.
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Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
Post holes
The “Post holes” value used in this tool’s formula. Adjust it to see results update live.
Hole diameter (in)
The “Hole diameter (in)” value used in this tool’s formula. Adjust it to see results update live.
Hole depth (in)
The “Hole depth (in)” value used in this tool’s formula. Adjust it to see results update live.
Bag yield (cu ft)
The “Bag yield (cu ft)” value used in this tool’s formula. Adjust it to see results update live.
Cost per bag
One-time or recurring costs that affect total money paid.
- bagCost
Cost per bag ($)
The “Cost per bag ($)” field. Default 5; typical range 2–20.
How this calculator works
Bags of concrete for cylindrical post holes. Planning estimates only — verify measurements and local codes on site. Cu ft per hole = π × (d/2)² × depth; bags = total cu ft ÷ bag yield. Example: 6 holes, 10 in diameter, 36 in deep → ~4.5 cu ft, ~8 bags.
Cu ft per hole = π × (d/2)² × depth; bags = total cu ft ÷ bag yield.
Example: 6 holes, 10 in diameter, 36 in deep → ~4.5 cu ft, ~8 bags.
When to use this Post Hole Concrete
Common use cases
- Bags of concrete for cylindrical post holes.
- Sanity-check with this case: 6 holes, 10 in diameter, 36 in deep → ~4.5 cu ft, ~8 bags.
- The relationship is: Cu ft per hole = π × (d/2)² × depth; bags = total cu ft ÷ bag yield.
Localized examples
- Masonry & Concrete: the example on this page uses the same formula as the widget.
What you get
- Fields: Post holes, Hole diameter (in), Hole depth (in), Bag yield (cu ft)
- Cu ft per hole = π × (d/2)² × depth; bags = total cu ft ÷ bag yield.
- Example on the page: 6 holes, 10 in diameter, 36 in deep → ~4.5 cu ft, ~8 bags.
How to Calculate Post Hole Concrete Step-by-Step
- 1Enter Post holes, Hole diameter (in), Hole depth (in), then the remaining fields. Use the values you have, not a catalog average, unless that is all you know.
- 2Cu ft per hole = π × (d/2)² × depth; bags = total cu ft ÷ bag yield.
- 3Worked case: 6 holes, 10 in diameter, 36 in deep → ~4.5 cu ft, ~8 bags.
- 4Buy materials after you walk the job. This is a first-pass quantity, not a purchase order.
Governing formula
Cu ft per hole = π × (d/2)² × depth; bags = total cu ft ÷ bag yield.
6 holes, 10 in diameter, 36 in deep → ~4.5 cu ft, ~8 bags.
Example: set Post holes = 6, Hole diameter (in) = 10, Hole depth (in) = 36, then read the result.
Variable definitions
- holeCount
Post holes
The “Post holes” field. Default 6; typical range 1–100.
- diameterIn
Hole diameter (in)
The “Hole diameter (in)” field. Default 10; typical range 6–24.
- depthIn
Hole depth (in)
The “Hole depth (in)” field. Default 36; typical range 12–48.
- bagYieldCuFt
Bag yield (cu ft)
The “Bag yield (cu ft)” field. Default 0.6; typical range 0.4–1.
- bagCost
Cost per bag ($)
The “Cost per bag ($)” field. Default 5; typical range 2–20.
- The takeoff (Cu ft per hole = π × (d/2)² × depth; bags = total cu ft ÷ bag yield.) ignores waste, code, and what you find when you open the wall. Measure twice on site.
- Nothing here is uploaded for the calculation itself.
Frequently Asked Questions
Cu ft per hole = π × (d/2)² × depth; bags = total cu ft ÷ bag yield.
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Reviews & Ratings
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4.8
out of 5.0
4 reviews
Daniel R.
Feb 28, 2026
Very usable on mobile. Would love a save/export option later, but the math feels solid.
Priya S.
Feb 3, 2026
The FAQ section answered my questions before I even had to search. Smooth dark mode too.
Marcus L.
Jan 19, 2026
Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.
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