How to use it
- Enter hole diameter in inches, depth in feet, post width in inches, and number of posts.
- Click Calculate to see bags, cubic feet, and cubic yards.
- Review the results and round up to the next whole bag.
The Post Hole Concrete Calculator takes your hole dimensions and post size to tell you exactly how much concrete mix you’ll need. Knowing the required 80‑lb bags prevents over‑ordering, saves money, and ensures the post is set with enough strength. The tool outputs three useful units: the number of 80‑lb bags (each 0.6 ft³), total cubic feet, and cubic yards for larger projects. Simply plug in the diameter, depth, post width, and quantity, then read the results. The bag count is always rounded up, because you can’t purchase a fraction of a bag. Use the cubic‑yard figure when ordering bulk material or comparing to supplier quotes. This quick, free calculator removes guesswork and keeps your project on budget.
Pro tips
- Add a 10% waste allowance to cover spillage and settling.
- Always round the bag total up to the next whole bag.
- Order a few extra bags in case the hole dimensions change.
- Double‑check that the hole diameter is measured at the widest point.
Real-life examples
- A homeowner installing a 4‑ft fence needs to know how many bags for six 6‑in holes.
- A contractor setting wooden deck posts wants to bulk‑order concrete by the yard.
- A landscaper calculating concrete for a row of garden trellis posts.
Case study
Mike needed concrete for eight 6‑in, 4‑ft deep holes. The calculator showed 2 bags per hole (1.32 ft³), so he ordered 16 bags total, saved $30, and finished the fence on schedule.