Concrete Calculator — Cubic Yards, Bags & Cost
Enter a slab, footing, column, stair, or mixed pour and see concrete cubic yards immediately, then refine waste, truck loads, bags, and cost.
20 × 12 ft slab, 4 in thick · 7% allowance
Standard concrete mix bags
including the selected allowanceTypical yields for standard concrete mix; verify the yield printed on your bag. Source: QUIKRETE Concrete Mix product data.
Slab, patio, or pad
Use length and width, or enter the known area of one pour. Thickness and quantity apply to each identical pour.
Wall, curb, or continuous footing
Use the total centerline length for all connected runs.
Round or square columns
Calculate piers, posts, or sonotube fills with identical dimensions.
Solid concrete stairs
Calculate identical rectangular steps plus an optional top landing.
Mixed rectangular sections
Add grade beams, pads, landings, thickened edges, or other rectangular pieces.
Already know the concrete volume?
Enter the total volume from your drawing or estimate. We will calculate bags, truck loads and costs using the settings below.
If your estimate already includes waste, set the order allowance to 0% to avoid adding it twice. The volume is the total for the project, not per section.
Order allowance
Truck, bags, and cost settings
Volume diagram
Order breakdown
| Element | Quantity | Net volume |
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Concrete calculator for cubic yards and cubic meters
Choose a construction shape and unit system. Every input is converted to cubic meters internally, then shown in cubic yards, cubic feet, or metric volume without mixing units. For several patios, pads, or floor-plan sections, total their footprint first with the square feet calculator, then use that measurement to check each slab thickness.
If your slab design includes a separate gravel base, estimate that layer with the gravel calculator. Use the base layer’s own area and specified depth, then compare bulk delivery with bags. Keep its quantity and cost separate from the concrete order.
Slabs, footings, columns, and stairs
Slabs and footings use rectangular volume. Round columns use a circular cross-section. Solid stairs sum the growing volume of each tread and can include a top landing.
Building a masonry wall above the footing? Estimate its units, pallets and installation mortar separately with the brick and block calculator. Use the footing dimensions from your project design; these tools estimate material quantities.
Ready-mix trucks or dry bags
The calculator shows two separate purchase estimates. Ready-mix cost uses the exact order volume plus the entered delivery fee for every required truck load. Dry-mix cost uses whole bags rounded up from the mixed yield printed on the package. Do not add the two totals together.
How much extra concrete should I order?
A 5–10% allowance is common, but uneven subgrade, forms, pumping, spillage, and dimension uncertainty can require more. Confirm quantities with the supplier and project professional.
Frequently asked questions
How many cubic yards are in a cubic foot?
One cubic yard contains 27 cubic feet. The calculator converts the net geometric volume before adding the selected waste allowance.
How many bags of concrete do I need?
Enter the mixed yield per bag shown by the manufacturer. The calculator divides order volume by that yield and rounds up to a whole bag.
Does this calculate reinforcement or structural capacity?
No. It estimates concrete volume and purchasing quantities only. Reinforcement, mix design, thickness, drainage, frost depth, and structural capacity require project-specific design.
Why might a supplier quote a different truck count?
Truck capacity, minimum loads, legal payload, short-load charges, and delivery sequencing vary. Enter the usable truck capacity supplied by your ready-mix company.
How is delivery included in ready-mix cost?
The entered delivery fee is multiplied by the number of truck loads. Use zero when delivery is already included, and add any one-time project or pumping fees outside the calculator.
Method and limitations
Results are material estimates based on entered geometry. Field dimensions, excavation, forms, compaction, and supplier rules control the actual order. This calculator is not engineering advice.
