Enter the job shape and dimensions to estimate concrete volume, whole bags, ready-mix volume, waste, and rough cost.
Choose the shape closest to the concrete you are ordering. Structural sizing still needs local code or project drawings.
Add a price to estimate cost.
Saved concrete estimates stay in this browser only.
This tool is for ordering material, not for designing the structure. It is useful for early takeoffs, shopping lists, and quick comparisons between bags and ready-mix.
The calculator finds geometric concrete volume, adds your waste factor, and then converts the result to bags or ready-mix volume.
A 12 ft by 10 ft slab at 4 in thick is 40 ft3 before waste. With 10% waste and 80 lb bags, it needs 74 bags.
Four 12 in holes, 36 in deep, with 4 in posts use about 8.38 ft3 before waste.
A 30 ft footing that is 16 in wide and 8 in deep is about 26.67 ft3 before waste.
Length and width use feet in imperial mode, while slab thickness, diameters, and trench depth use inches.
Uneven ground, form gaps, spillage, and supplier rounding can leave you short if you order the exact measured volume.
The preset yields are common estimates. Product labels and data sheets are the better source for the exact bag you buy.
The calculator does not choose slab thickness, reinforcement, footing size, frost depth, or soil bearing values.
The result shows cubic yards and cubic meters so you can compare your estimate with a supplier's preferred unit.
If bags are sold by kilograms or liters in your area, choose custom yield and enter the package coverage.
Save a bagged estimate and a ready-mix estimate before changing dimensions or waste.