How to use it
- Enter length in feet, width in feet, and thickness in inches.
- Click the Calculate button.
- Read the cubic yards, cubic feet, and bag count results.
What it does – You enter the length, width and thickness of the slab and the tool instantly returns three units you’ll need to order: cubic yards, cubic feet and the number of 80‑lb bags. Why it matters – Ordering too little means delays; ordering too much wastes money and space. Knowing the exact volume lets you budget accurately and schedule deliveries. How to read the results – Cubic yards is the standard measure for concrete trucks. Multiply cubic yards by 27 to see the total cubic feet if you prefer that scale. Divide the cubic‑feet total by 0.6 to see how many 80‑lb bags are required. Round up to the next whole bag for a safe margin. Add a 5‑10% waste allowance for cuts and uneven subgrade to avoid shortfalls.
Pro tips
- Include a 5‑10% waste factor for cuts, spillage, and uneven subgrade.
- Round up the bag count to the next whole bag; you can’t order a fraction.
- Order concrete a day before pour to ensure fresh mix and avoid delays.
- Double‑check thickness; a common mistake is entering inches as feet.
Real-life examples
- A homeowner planning a 12 ft × 16 ft patio 4 in thick.
- A contractor estimating concrete for a 30 ft × 40 ft warehouse floor 6 in thick.
- A landscaper needing a 10 ft × 10 ft stepping stone base 3 in thick.
Case study
Mike needed a 200‑sq‑ft driveway 5 in thick. Using the calculator he saw he required 3.7 cubic yards, which translates to 18 bags. He ordered 19 bags, avoided a costly second delivery, and finished on schedule.