How to use it
- Enter the slab length in feet.
- Enter the width in feet.
- Enter the thickness in inches.
- Read cubic feet, cubic yards and bag count results.
What it does – The Bigfoot Footing Concrete Calculator converts the length, width and thickness of a slab into three useful units: cubic feet, cubic yards, and the number of 80‑lb bags of mix. Why it matters – Knowing the exact volume prevents over‑ordering (wasting money) or under‑ordering (causing project delays). How to read the results – Cubic feet is the raw volume, divide by 27 to see cubic yards (the unit most suppliers quote). Multiply cubic feet by 1⁄0.6 (or divide by 0.6) to get the bag count; round up to the nearest whole bag. The calculator does all conversions instantly, so you can plan your purchase with confidence.
Pro tips
- Add 5‑10% extra for spillage and compaction.
- Always round the bag total up—you can’t buy a fraction of a bag.
- Order bags in full pallets when possible to reduce delivery fees.
- Double‑check thickness conversion (inches to feet) before entering.
Real-life examples
- A homeowner pouring a 12 ft × 16 ft patio 4 in thick.
- A contractor estimating concrete for a 24 ft × 30 ft warehouse floor slab.
- A DIYer planning a 6 ft × 8 ft shed foundation 6 in thick.
Case study
Mike needed a 10 ft × 12 ft slab 4 in thick for his workshop. Using the calculator he saw he required 40 ft³, 1.48 yd³ and 67 bags, so he ordered 70 bags and finished on schedule without extra trips.