How to use it
- Enter the hole diameter in inches.
- Enter the depth in feet and the number of holes.
- Read the cubic‑yard, bag, and cubic‑foot results instantly.
What it does – The Cement Post Hole Calculator turns the diameter, depth, and quantity of holes you enter into three practical results: total concrete volume in cubic yards, the equivalent number of 80‑lb bags, and the volume in cubic feet. Knowing these numbers lets you order the right amount of mix, avoid costly over‑orders, and keep your project on schedule. You can also adjust for a 5% waste factor to ensure you have enough material on site. The calculator uses the standard that one 80‑lb bag yields about 0.6 ft³ of concrete, then converts the total cubic‑feet volume to cubic yards (1 yd³ = 27 ft³). How to read – Cubic yards give you a bulk‑order metric, bags tell you how many bags to buy, and cubic feet help you visualize the space each hole occupies.
Pro tips
- Add a 5% waste allowance to cover spillage and variations.
- Round up the bag count; you can’t buy a fraction of a bag.
- Order bags in multiples that match delivery truck capacities to save freight costs.
- Double‑check the diameter and depth units before calculating.
Real-life examples
- A homeowner installing a fence needs to know how many concrete bags to buy for post holes.
- A landscape contractor estimating material for a row of garden lights.
- A small business owner budgeting for a new parking‑lot sign post.
Case study
Mike, a DIY homeowner, entered a 4‑inch diameter and 3‑foot depth for 12 fence posts. The calculator showed 0.8 cubic yards, 14 bags, and 21 cubic feet, letting him order exactly the right amount and finish his fence on schedule.