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 calculator turns the dimensions of a slab or footings into three useful measures: cubic yards of concrete, the number of 80‑lb bags, and total cubic feet. Knowing cubic yards tells you how much material to order from the mixer, while bag‑type deliveries help you budget for bag‑type deliveries. The cubic‑feet figure is handy for estimating waste or comparing against ready‑mix specs. Simply type length, width, and thickness; the tool instantly shows the three results. For example, a 10 ft × 12 ft slab 4 in thick equals 40 ft³, about 1.48 yd³, requiring roughly 67 bags (40 ÷ 0.6). Read the numbers, add a small waste allowance, and place your order with confidence. You can also convert the yardage to metric if needed, or compare multiple design options side by side. The results are displayed with two decimal places for precision, but you can round up to the nearest whole bag to ensure you have enough material.
Pro tips
- Add 10% extra volume for waste and spillage.
- Always round up the bag count to the next whole bag.
- Order bags in full pallets when possible to lower shipping costs.
- Convert thickness from inches to feet by dividing by 12 before entering.
Real-life examples
- Homeowner pouring a 12 ft × 16 ft patio 5 in thick.
- Contractor estimating concrete for a 20 ft × 30 ft warehouse floor.
- DIYer planning a 6 ft × 8 ft driveway slab 3 in thick.
Case study
Mike needed a 10 ft × 14 ft patio 4 in thick. Using the calculator he saw he required 1.63 yd³, about 73 bags. He ordered 75 bags, saved a day of re‑ordering, and finished on budget.