How to use it
- Enter length in feet.
- Enter width in feet.
- Enter thickness in inches.
- Read cubic yards, bags, and cubic feet results.
What it does: The Sq Ft Concrete Calculator turns your slab dimensions into three practical measures—cubic yards for ordering, bags for budgeting, and cubic feet for verification.
Why it matters: Knowing the exact yardage prevents over‑ordering (which wastes money) and under‑ordering (which delays projects).
How to read the results: Cubic yards is the volume you’ll give to the supplier; bags is the number of 80‑lb mixes (each 0.6 ft³); cubic feet lets you double‑check against your own calculations. The tool assumes a standard 80‑lb bag yields 0.6 ft³, so the bag count is simply the total cubic feet divided by that constant, rounded up to the nearest whole bag. This matches what most suppliers quote, so your order aligns with real‑world pricing. Use the calculator before you call a concrete company, and you’ll have the exact numbers to get an accurate quote and avoid surprise extra costs.
Pro tips
- Add a 10% waste allowance for cuts and uneven subgrade.
- Round up the bag count to the next whole bag; you can’t order a fraction.
- Order concrete a day ahead to secure delivery windows.
- Double‑check thickness conversion (inches to feet) before entering.
Real-life examples
- A homeowner pouring a 12 ft × 10 ft patio 4 in thick.
- A contractor estimating concrete for a 30 ft × 20 ft warehouse slab 6 in thick.
- A DIY enthusiast planning an 8 ft × 6 ft garden walkway 3 in thick.
Case study
Mike needed a 12 × 10 ft patio 4 in thick. Using the calculator he saw he required 1.5 yd³, which translates to 67 bags. He ordered exactly that amount, saved $200 on excess material, and the pour finished on schedule.