How to use it
- Enter the length in feet
- Enter the width in feet
- Enter the thickness in inches
- Read the cubic yards, cubic feet, and bag count results
The Lowes Concrete Bag Calculator turns your slab dimensions—length, width, and thickness—into three useful numbers: total cubic yards, total cubic feet, and how many 80‑lb bags you’ll need. Knowing the cubic yards helps you compare estimates from contractors, while the bag count tells you exactly how many bags to order, avoiding over‑or under‑buying. The calculator uses the standard that each 80‑lb bag yields about 0.6 cubic feet, so the results are realistic for typical mixes. Simply enter feet for length and width, inches for thickness, and watch the instant conversion. Read the cubic yards to gauge overall volume, the cubic feet for detailed planning, and the bag total to place a precise order. By basing your purchase on these exact figures you eliminate guesswork, keep your budget tight, and ensure the job stays on schedule.
Pro tips
- Add a 10% waste allowance for cuts and breakage
- Round up the bag total to the next whole bag
- Order an extra bag if you’re near a full bag threshold
- Double‑check thickness units; inches vs. feet cause big errors
Real-life examples
- Homeowner pouring a 10 ft × 12 ft garage floor
- Contractor estimating material for a 20 ft × 30 ft commercial slab
- DIY enthusiast building a concrete countertop
Case study
Mike needed a 12 ft × 8 ft patio 4 in thick. Using the calculator, he saw he required 2.2 cubic yards, 4.0 cubic feet, and 7 bags. He ordered exactly 7 bags, saved $30 on excess material, and finished on time.