How to use it
- Enter length in feet.
- Enter width in feet.
- Enter thickness in inches.
- Click Calculate to see results.
What it does – The calculator turns the length, width, and thickness of your slab into three practical measurements: total cubic feet, cubic yards, and the number of 80‑lb bags needed. Why it matters – Knowing cubic yards lets you order the right amount from suppliers, while bag count helps you budget if you’re mixing on‑site. How to read – The cubic‑feet figure is the raw volume of the slab. The cubic‑yard value is the same volume expressed in the unit most concrete companies quote. The bag total uses the constant that one 80‑lb bag yields about 0.6 ft³, so the calculator divides the cubic‑feet result by 0.6 and rounds up. Use the numbers to place an accurate order and avoid costly over‑or under‑pours.
Pro tips
- Add 10% extra for waste and spillage.
- Always round bag count up to the next whole bag.
- Order a little more than the cubic‑yard total to cover settling.
- Double‑check thickness entry; mixing inches vs feet is a common error.
Real-life examples
- A homeowner plans a 12 ft × 10 ft patio 4 in thick and needs material quantities.
- A contractor estimating a garage floor 20 ft × 15 ft at 6 in depth.
- A landscaper preparing a raised garden bed 8 ft × 6 ft with a 3‑in slab.
Case study
Mike needed a 10 × 8 ft patio 5 in thick. Using the calculator he saw he required 2.3 cubic yards, which translated to 4 bags (rounded up). He ordered 3 cubic yards, saved $150, and completed the pour without running short.