How to use it
- Enter the hole diameter in inches.
- Enter the depth in feet.
- Enter the number of holes.
- View cubic yards, cubic feet, and required 80‑lb bags.
This calculator turns the dimensions of your post holes into the exact amount of concrete you’ll need. You input the hole diameter, depth, and how many holes you’re digging; the tool instantly returns the total volume in cubic feet, converts that to cubic yards for ready‑mix orders, and tells you how many standard 80‑lb bags are required (each bag provides about 0.6 ft³). Knowing these numbers prevents over‑ordering, saves money, and keeps your project on schedule. The cubic‑yard figure matches the units suppliers use, while the bag count lets you order the right number of packages, rounding up to the nearest whole bag. Use the results to plan delivery, budget, and site logistics with confidence.
Pro tips
- Add 10 % extra for spillage and compaction.
- Round up the bag count to the next whole bag.
- Order a full truckload if total bags exceed 30 to get bulk pricing.
- Double‑check diameter units; the calculator expects inches, not centimeters.
Real-life examples
- A homeowner installing a 6‑inch fence post line.
- A contractor setting wooden deck footings across a patio.
- A landscaper anchoring garden lights with 4‑inch post holes.
Case study
John needed 12 fence posts, each 6 in diameter and 3 ft deep. Using the calculator, he saw he required 4 bags of 80‑lb mix instead of guessing 6, saving $30 and avoiding leftover concrete.