How to use it
- Enter length (ft), width (ft) and thickness (in).
- Click the Calculate button.
- Read the cubic‑yard, cubic‑foot and bag results.
- Add a waste allowance if needed.
What it does
The tool takes your slab dimensions and instantly converts them to cubic feet, cubic yards, and the number of 80‑lb bags required. Knowing the exact volume helps you budget material costs and avoid costly over‑orders.
Why it matters
Cubic yards are the standard unit for concrete delivery quotes, while cubic feet let you see the raw volume. The bag count translates that volume into the most common retail package, so you can order the right amount from the store.
How to read the results
- Cubic feet – raw volume of your slab.
- Cubic yards – divide cubic feet by 27; this is what the truck driver will quote.
- Bags – divide cubic feet by 0.6 (each 80‑lb bag = 0.6 ft³) and round up.
Pro tips
- Add 5‑10% extra for waste and spillage.
- Always round bag count up to the next whole bag.
- Order an extra bag for mix‑time adjustments.
- Double‑check thickness is entered in inches, not feet.
Real-life examples
- A homeowner planning a 12 ft × 15 ft patio needs to know how many bags to buy.
- A contractor pouring a 20 ft × 30 ft garage floor wants the delivery volume in cubic yards.
- A DIYer building a shed foundation wants to budget concrete material before ordering.
Case study
Sam entered his 10 × 20 ft slab at 4 in thick, got 2.96 cubic yards and 133 bags, rounded up to 135 bags, and ordered exactly what the supplier quoted—saving $150 and avoiding a second delivery.