How to use it
- Enter length in feet, width in feet, and thickness in inches.
- Press Calculate to see cubic feet, cubic yards, and number of 80‑lb bags.
- Review the results and round up for ordering.
Enter your slab dimensions and the calculator instantly converts them to the three units contractors use daily. It first finds the volume in cubic feet, then divides by 27 to give cubic yards, and finally divides by 0.6 to show how many 80‑lb bags are required. Knowing the exact cubic yards helps you get accurate delivery quotes, while the bag count tells you how many mixes to order. The results are displayed side‑by‑side so you can compare and decide whether to add a waste allowance. No guesswork, no extra calls—just the numbers you need to place a confident order. Cubic yards are the standard unit for ready‑mix deliveries, so quoting this number to a supplier avoids over‑ or under‑ordering. The bag count is useful if you’re mixing on‑site with 80‑lb bags, letting you purchase the exact quantity. Cubic feet can be handy for estimating space in a pit or for comparing against existing material.
Pro tips
- Add 5‑10% extra for spillage and uneven subgrade
- Round bag count up to the next whole bag
- Order concrete a day early to avoid delivery delays
- Double‑check thickness conversion from inches to feet
Real-life examples
- A homeowner pouring a 6‑ft‑by‑10‑ft patio 4‑in thick
- A contractor estimating concrete for a 12‑ft‑wide driveway 6‑in thick
- A landscaper calculating fill for a garden bed 2‑ft deep
Case study
Sam entered a 10 × 12 ft patio at 4 in thickness, got 0.44 cubic yards and 22 bags, ordered 25 bags, and avoided a costly second delivery.