Enter your slab's Length, Width, and Depth/Thickness, set your Mix Ratio and Waste Factor, and the Concrete Mix Calculator breaks down your Total Concrete Volume into exact quantities of Cement, Sand, and Gravel Needed — plus how many 94 lb Cement Bags to grab before you pour.
Total Concrete Volume
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Cement Needed
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Sand Needed
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Gravel Needed
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Cement Bags (94 lb)
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Mix ratios show the proportion of cement:sand:gravel by volume. For example, 1:3:6 means 1 part cement, 3 parts sand, and 6 parts gravel. Higher cement ratios create stronger concrete but cost more.
For a 4-inch thick slab, you need about 0.012 cubic yards per square foot. A 10x10 foot area (100 sq ft) would require approximately 1.2 cubic yards of concrete.
Yes, always order 5-10% extra concrete to account for spillage, uneven surfaces, and measurement variations. It's better to have slightly too much than to run short during a pour.
Wet volume is the final concrete volume after mixing. Dry volume is about 54% larger because the materials compact when mixed with water. Our calculator accounts for this automatically.
A standard 94-pound bag of Portland cement contains approximately 1 cubic foot of material. The calculator converts cubic yard requirements to bag quantities for easy purchasing.
Yes, this calculator works for any rectangular concrete project including slabs, footings, walls, and sidewalks. Just enter the length, width, and thickness dimensions.
Use 1:5:10 for light-duty projects, 1:3:6 for standard slabs and walkways, 1:2:4 for driveways and heavy-duty applications, and 1:1.5:3 for high-strength structural work.
The calculator uses feet for length/width and inches for depth by default. Results are shown in cubic yards, which is the standard unit for ordering concrete from suppliers.