How to use it
- Enter length, width and thickness in the fields provided.
- Enter the price per cubic yard of concrete.
- Click the Calculate button to see cubic yards, cost, bags and cubic feet.
What it does – The calculator turns your slab dimensions into the exact concrete volume in cubic yards, then multiplies by the price you provide to give an estimated cost. It also tells you how many 80‑lb bags you’ll need (each bag = 0.6 ft³) and the total cubic feet. Why it matters – Knowing volume and cost before you order prevents over‑buying, saves money, and keeps projects on schedule. How to read the results – Cubic yards is the standard ordering unit; Estimated cost is price × cubic yards; Bags is cubic feet ÷ 0.6, rounded up; Cubic feet is a quick check of the raw volume. The tool automatically converts inches to feet (divide thickness by 12) and then to cubic yards (divide cubic feet by 27). Results are shown to two decimal places for precision, but you can round up when ordering to avoid shortfalls.
Pro tips
- Add a 10% waste allowance to the bag count.
- Always round up the number of bags to the next whole bag.
- If total volume is 0.9 yd³ or more, order a full cubic yard to simplify delivery.
- Double‑check thickness conversion; 4 in = 0.33 ft.
Real-life examples
- A homeowner planning a 10 ft × 12 ft patio with 4 in thickness needs to know how many bags to buy.
- A contractor estimating material cost for a 200 ft² garage slab.
- A landscaper ordering concrete for a garden walkway and wants to avoid over‑ordering.
Case study
Jane measured her 12 ft × 15 ft driveway at 3 in thick, entered the numbers, and the calculator showed 1.33 yd³, $160 cost and 74 bags. She ordered 75 bags, saved $30 on waste, and completed the job on schedule.