How to use it
- Enter length in feet.
- Enter width in feet.
- Enter thickness in inches.
- Read cubic yards, cubic feet, and bag count.
This calculator takes the three dimensions you provide—length, width and slab thickness—and instantly returns three practical results: the total concrete in cubic feet, the equivalent in cubic yards, and how many standard 80‑lb bags are required. Knowing the cubic‑yard figure lets you compare directly with supplier quotes, while the bag count helps you order the right amount of mix without over‑buying. The results are based on the exact conversion that each 80‑lb bag yields about 0.6 cubic feet, so you can trust the numbers for budgeting and planning. Simply read the three outputs, round up the bag total, and you’re ready to place an accurate order.
Pro tips
- Add 5‑10% extra for waste and spillage.
- Round the bag count up to the next whole bag.
- Order a little extra to cover minor mis‑measurements.
- Double‑check thickness; a common mistake is entering inches as feet.
Real-life examples
- A homeowner pouring a 4‑ft by 6‑ft patio slab 4 in thick.
- A contractor estimating concrete for a 10‑ft wide driveway 6 in deep.
- A DIY gardener building a 3‑ft by 8‑ft raised garden bed 2 in thick.
Case study
Mike entered his 8 ft × 12 ft patio dimensions with a 4‑in thickness, got 0.89 cubic yards and 53 bags, ordered 55 bags, and finished on budget without a costly shortfall.