How to use it
- Measure and enter your slab's length in feet.
- Enter the width of your pour in feet.
- Enter your planned slab thickness in inches.
- Read your total volume in cubic feet, yards, and required 80-lb bags.
Under-ordering concrete stops your pour halfway through. Over-ordering wastes hard-earned cash on heavy bags you have to haul back. This tool eliminates guesswork before you drive to the home improvement store. Enter your project dimensions to get your exact volume in cubic feet and cubic yards, alongside the exact number of standard 80-lb bags required. Because each standard 80-lb bag yields about 0.6 cubic feet, knowing your exact cubic footage prevents costly mid-project dry joints. Use the cubic yard total if you cross the threshold into ordering a ready-mix truck instead of mixing by hand. Treat the bag count as your baseline material purchase, then add a small buffer for uneven ground. You get your project planned in seconds, purchase the exact quantity needed, and pour with total confidence.
Pro tips
- Add 10% extra material to cover uneven subgrades, form bowing, and accidental spillage.
- Always round fractional bag results up to the next full bag to avoid structural cold joints.
- Switch to ready-mix truck delivery if your project requires more than 45 to 50 bags.
- Measure depth across multiple excavation points to ensure your thickness input represents the deepest sections.
Real-life examples
- Pouring a 10x10-foot backyard concrete patio slab at 4 inches thick.
- Setting a solid foundation base for an outdoor storage shed or hot tub pad.
- Replacing broken sidewalk segments or pouring a new garden pathway.
Case study
Dave needed to pour a 12x12-foot patio slab at 4 inches thick (48 cubic feet). Instead of guessing bag counts in the store aisle, he ran the numbers through the calculator. It showed an exact requirement of 80 bags (at 0.6 cubic feet per 80-lb bag). Dave bought 88 bags to cover grade variations, finished the pour smoothly, and avoided mid-pour emergency runs.