How to use it
- Enter length in feet.
- Enter width in feet.
- Enter thickness in inches.
- Read cubic yards, cubic feet, and bag count.
With this free tool you simply plug in the length, width and thickness of the slab you plan to pour. The calculator converts those dimensions to total volume in cubic feet, then to cubic yards (27 ft³ = 1 yd³) and finally divides by the 0.6 ft³ per 80‑lb bag to show how many bags you’ll need. Knowing the exact cubic yards helps you order the right amount of ready‑mix or hire a crew, while the bag count prevents costly over‑ordering. The results are displayed in three columns: Cubic Yards, Cubic Feet, and Bags. Use the numbers to compare supplier quotes, schedule deliveries, and add a small waste allowance. The interface updates instantly as you change any dimension, so you can experiment with different slab sizes before you commit.
Pro tips
- Add 5‑10% extra for spillage and breakage.
- Round up the bag total; you can’t buy a fraction of a bag.
- Order bags from the same supplier to avoid mix inconsistencies.
- Double‑check thickness conversion from inches to feet before entering.
Real-life examples
- A homeowner estimating material for a 4‑inch‑thick patio slab.
- A contractor pricing a 6‑inch‑thick garage floor.
- A landscaper planning a concrete retaining wall base.
Case study
Sam needed a 10 ft × 12 ft × 4 in patio. The calculator showed 1.48 yd³, 4.9 ft³, and 8 bags. He ordered 8 bags, avoided a $150 over‑order, and completed the job on schedule.