Calculate concrete volume for slabs, footings, walls, columns, tubes, and solid stairs. Add a waste allowance and optionally estimate bags or concrete material cost.
Choose your concrete shape, enter its measurements, and calculate the volume. Add optional bag yield or pricing details when you need a material estimate.
Choose a slab, circular pad, column, wall, hollow cylinder, or solid stairs. The diagram and input fields update for your selection. Check the note beneath the diagram to confirm that the shape matches your project.
Select the unit beside each dimension before entering its value. Use Number of identical items for matching pieces, or Add Another Item for a different shape or size. Count shared or overlapping concrete volumes only once.
Adjust the waste allowance for your project. Open Estimate concrete bags to enter the mixed yield per bag, or Estimate concrete cost to add pricing. A price per bag also requires the bag-yield input.
Select Calculate Concrete to see net volume, volume including allowance, and conversions. Review the item breakdown and any bag or cost estimate. Recalculate after changing inputs, or select Clear All to start again.
Check your measurement units: Each dimension has its own unit. For example, you can enter slab length and width in feet and thickness in inches. Changing a unit does not convert the existing number; changing a shape clears that item’s dimensions.
See how slab length, width, and thickness determine concrete volume, then add an allowance to estimate your material needs.
This example uses a uniform 4-inch thickness, one slab, and a 10% waste allowance. The dimensions and allowance are example inputs, not design recommendations.
Approximately 1.25 m³ or 44 ft³. Confirm your supplier’s order increments before ordering.
Convert length, width, and thickness to the same unit before multiplying them.
Length × Width × Thickness
Square footage measures the slab’s footprint. Concrete volume also needs thickness. Entering 4 inches as 4 feet would greatly overestimate the required concrete.
Include changes in depth: This example assumes a uniform slab. Calculate additional concrete in thickened edges or deeper sections separately, adding only the volume not already included in the main slab.
Use your calculated volume to estimate bags or ready-mix concrete, then check product yield, pricing, and delivery quantities before ordering.
Enter the volume of mixed concrete produced by one bag. Use the yield for your exact product and bag size. The calculator divides the volume including allowance by that yield and rounds up to whole bags.
Use the result in cubic yards or cubic meters when discussing a ready-mix order. Ask your supplier about minimum quantities, order increments, delivery access, and any charges for smaller loads.
Review uneven excavation, changes in depth, and potential material losses when choosing an allowance. Add thickened edges or deeper sections as separate items, including only the volume not already counted.
Enter a price per cubic yard, cubic meter, cubic foot, or bag. Volume pricing uses the total with allowance; bag pricing uses the rounded bag quantity. Keep delivery and other project charges separate.
Find answers about concrete volume, measurement units, bag estimates, and the shapes supported by this calculator.
Multiply the slab’s length, width, and thickness using the same measurement unit. Dimensions in feet give cubic feet; divide that result by 27 for cubic yards. Dimensions in meters give cubic meters. In this calculator, select each dimension’s unit separately and the conversions are handled automatically.
Yes. Each dimension has its own unit selector. For a 12 ft × 10 ft slab that is 4 inches thick, select feet for length and width, and inches for thickness. Changing a selector does not convert a number already entered, so update the number if needed.
The calculator starts at 10%, which you can adjust. Review your measurements, excavation, and potential material losses when choosing an allowance. Measure known deeper sections separately rather than relying on a percentage to cover them. The allowance is applied once to the combined net volume.
Divide the volume including allowance by the mixed concrete yield of one bag, then round up. Open Estimate concrete bags and enter the yield listed for your exact product and bag size. Use a yield volume, such as cubic feet or liters, rather than entering the bag’s weight.
Yes. Use Add Another Item for a different shape or size. Use Number of identical items for pieces with matching dimensions. The calculator adds their net volumes before applying the allowance. Overlapping volumes are not detected automatically; include shared concrete only once.
The Solid stairs option assumes equal tread depths and riser heights, with concrete filling the entire space beneath each step down to a level base. It excludes landings, extra base thickness, and stairs with a sloped underside. Do not use that option for a hollow stair structure or a thin stair slab.
No. The Concrete wall option calculates a solid rectangular volume. For a wall with openings, divide the remaining concrete into non-overlapping rectangular sections and add those sections as separate items. Avoid entering the full wall and those sections together.
A column is a solid cylinder. The Hollow cylinder / tube option calculates the concrete shell between an outer and inner diameter. If you are filling the inside of a tube form completely with concrete, choose Column / round footing and enter the form’s internal diameter as the concrete diameter.
Volume pricing multiplies the volume including allowance by your price per selected volume unit. Bag pricing multiplies the rounded bag quantity by the price per bag. Add delivery, pumping, labor, reinforcement, and taxes separately unless already included in your price. Currency selection does not perform an exchange-rate conversion.
The bag option estimates packaged concrete mix using its stated mixed yield. It does not calculate separate cement, sand, and aggregate quantities for a site-mixed recipe. It also does not select concrete strength, reinforcement, or structural dimensions.
Choose your project shape and enter its measurements. Get concrete volume with your selected allowance, plus optional bag quantities and material costs.
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