How to use it
- Enter length in feet.
- Enter width in feet.
- Enter thickness in inches.
- Click Calculate to see cubic yards, bags, and cubic feet.
What it does – The calculator takes the length, width and thickness of your slab and instantly gives you three useful volumes: total cubic feet, total cubic yards, and the number of 80‑lb bags of mix needed. Why it matters – Knowing the exact volume prevents ordering too little (which delays projects) or too much (which wastes money). How to read the results – Cubic feet is the raw volume; cubic yards is the same volume expressed in a larger unit commonly used by suppliers. The bag count is based on the standard that one 80‑lb bag yields about 0.6 cubic feet, so you can see exactly how many bags to order.
Pro tips
- Round up the bag count to the nearest whole bag.
- Add a waste allowance for spillage or cuts.
- Check local supplier minimum order sizes.
- Verify thickness measurement is consistent across the area.
Real-life examples
- A homeowner pouring a 10 ft × 12 ft patio 4 in thick.
- A contractor estimating concrete for a 30 ft × 40 ft warehouse floor 6 in thick.
- A landscaper planning a 5 ft × 8 ft stepping‑stone area 3 in thick.
Case study
John needed a 12 ft × 15 ft driveway 5 in thick. Using the calculator he saw he required 2.2 cubic yards, about 140 bags, and ordered exactly that, avoiding a $200 overrun.