Cubic Yards:
Cubic Meters:
50-lb Bags:
60-lb Bags:
80-lb Bags:
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Concrete, which is a mix of water, aggregate, and cement, is most commonly sold by the cubic yard but is also available in pre-mixed bags.
Concrete is used for many construction purposes, including foundations, stem walls, patios, or driveways. It’s also used to fill CMU blocks or to create countertops.
It’s important to calculate the amount of material needed as accurately as possible. Concrete must be poured at the same time; if you don’t have enough concrete for the pour, the resulting installation can be weak or need to be redone.
We’ll cover the process for estimating concrete in detail below, but you can also use the calculator above to simplify the process.
One cubic yard is equal to the volume of a cube with edges that are one yard (three feet) in length.
You might be wondering just how much concrete is in a cubic yard. A cubic yard is equal to 27 cubic feet or 46,656 cubic inches, or 45 80-lb bags.
Use the following formulas to calculate the concrete needed for various types of pours.
The volume of a rectangular space is equal to the length times the width times the height. For slabs, substitute the thickness for the height measurement.
The volume of a circular space is equal to pi times the radius squared times the height. The radius is equal to the diameter divided by two.
Stairs are generally poured as one complete unit. To find the volume, get the height of each step from the ground to the height of the step when looking at its side.
So the lowest step will have the shortest height, while the top step will have the tallest. Take the length and width of the top of each step, then multiply the height, width, and length of each step individually, then add them together to get the total volume for the unit.
So far, we’ve covered how to calculate yards, but if your project is small, you can use pre-mixed bags of concrete. Pre-mixed bags are sold by companies like Quikrete or Sakrete and come in 50-pound, 60-pound, or 80-pound sizes.
Using bags can be easier than ready-mix when you have many small pours or a small project where a truck is not practical or cost-effective. But keep in mind that mixing bags on-site can become difficult if you’re pouring a large slab or many footings.
For the most part, ready-mix concrete from a truck is more cost-effective than bags and makes sense if you have a mid-size project and can pour it all at once.
Much of the work to pour concrete is done before the truck even arrives at the project. You’ll need to measure and lay out the site and install forms to create the edges of a slab or contain a footing.
Plan a proper base using a gravel or stone calculator to estimate the right amount of base fill if needed.