Calculating Concrete

It might seem that calculating the amount of concrete needed for a pour seems like a daunting task. However, the process is not that difficult to understand, and will need to be figured out before starting any concrete placement project. It will help determine all the necessary concrete required to complete the job.

Ordering an insufficient amount of the required concrete may cause serious issues including the need to pour the concrete at two different times. The result of this could create serious problems, including structural weakness at the seam where both placements join. Alternatively, placing an order of too much concrete could create a huge waste of money. Luckily, there is a simple solution for figuring out exactly how much concrete is needed for the job.

**How Concrete Is Measured**

It is important to become familiar with exactly how concrete is measured in volume. Based on location, concrete is ordered in cubic yards or cubic meters. The process for either method of measurement is the same. Imagine that one cubic yard measures 3’ long in every dimension. This means that it is 3’ high, by 3’ wide, by 3’ deep, which calculates as 3’ x 3’ x 3’ or 27 cubic feet.

**Measuring the Site**

The next step in the process is to carefully measure every outside dimension of the concrete pouring site. This includes its length, width and depth in feet. If the outside shape is not a rectangle or square, mentally break apart each component of the entire project into specific rectangles or squares. This way, it will be easy to measure each area to determine its volume of concrete.

After de-constructing the entire project into specific rectangles or squares, each component can be calculated to determine its volume. As an example, if one specific rectangle slab measures 12’ (3.66 m) by 10’ (3.05 m) long by 4” (10.16 cm) deep, it can be easily calculated. The overall volume of the concrete will be determined by its length times its width, times its depth, which in this case is 12’ times 10’ times 1/3 (4”) of a foot. (V = L x W x D).

The calculation would play out as 12’ x 10’ x 1/3’, or 40 cubic feet. Next, convert the calculated volume from cubic feet into cubic yards. This process is simple. Simply take the 40 cubic yards and divide it by 27, which calculates to 40 / 27 = 1.48 cubic yards required for the poured concrete project. Multiply that number (1.48) by 1.05 for that little extra material if needed. This will provide 105% of the necessary amount for any extra in case of spillage, waste, or if the project was over-excavated.

Performing the calculation correctly before the concrete placement can minimize the need to make an additional pour in the event that not enough concrete was brought to the site. Through the basic steps of multiplication and division, calculating the amount of necessary concrete is a simple process.