A concrete bag is a ready-mix material that comprises cement, gravel, sand, and other ingredients. The number of concrete bags in one cubic foot depends on the size of the bag you choose.
Considering that the number of concrete bags differs for all sizes, such as 40lb, 50lb, 60lb, and 80lb bags, the number of concrete bags necessary for one cubic foot can range from 0.6 to 1.25 per cubic foot.
To ensure that you have enough material to cover the space needed, it is best to calculate your needs beforehand and buy a little extra so that you do not run out in the middle of your project.
So here, we will discuss the general calculation of concrete bags in one cubic foot according to the size. Also, we will estimate cubic feet in one 40lb, 50lb, etc., concrete bag, and vice versa.
General Evaluation Method To Find Out Concrete Bags In A Cubic Foot
There are around two different methods by which you can determine the number of concrete bags in one cubic foot. However, before we get into detail here are some important things to remember. One cubic foot is equal to 133 lbs of concrete.
It is decided on its density, which may vary by the way, according to the amount of gravel, sand, and aggregate.
(1 cubic foot = 133lbs concrete)
Method 1 – Using Weight/Size
You can take any size of the concrete bag such as 40, 50, 60, 80, or 90 lbs, and find out the number of concrete bags accordingly. You have the data regarding the size of your bag in lbs and also that one cubic foot is about 133 lbs substantial.
All you need to do is divide 133 lbs by the size (in lbs) of your concrete bag, and you will be getting the number of bags in a cubic foot.
Concrete bags in one cubic foot = 133 lbs / Size Of Concrete bag (lbs)
Method 2 – Using Cubic Feet Of One Concrete Bag
In this method, first, you have to evaluate the cubic feet covered in one bag of concrete according to its size. Later, you have to find the bags count for one cubic foot, then only divide 1 by the cubic feet you found in every bag size.
With that in mind,
Concrete bag count = 1 cubic foot / cubic feet in a concrete bag as per size (lbs)
Both methods will provide you with the same result – and are considered to be both correct. There’s no right or wrong method and it depends on which one works best for you. Some people prefer using the weight/size method, while others use the cubic feet of one concrete bag.
Understanding this will help you easily predict how much material you need for a particular area or job. Thus, let us check out how many bags of concrete (different sizes) are in a cubic foot.
How Many 40lbs Concrete Bags Are In A Cubic Foot?
Here, we will be trying both methods to get the result for a 40lbs concrete bag.
According to the general formula discussed above,
Concrete bags in 1 cubic feet = 133/40 = 3.32 bags
As per the above formula, we first have to find out cubic feet in a 40lbs concrete bag.
Cubic feet in a 40lbs bag = 40/133 (as one cubic foot = 133 lbs and we know the size of the bag is 40 lbs)
Therefore, the cubic feet in a 40 lbs bag = 0.3007 cubic feet.
Now add this value to the formula of counting concrete bags:
Number of concrete bags = 1/0.3007 = 3.32 bags
Hence, there are 3.32 concrete bags of 40 lbs size in cubic feet.
How Many 50lbs Concrete Bags Are In A Cubic Foot?
Calculations are similar to 40 lbs, so let us directly check the answer with both methods.
Method 1 – Applying the formula,
Concrete bags in one cubic foot = 133/50 = 2.66 bags.
Method 2 – Finding cubic feet in 50 lbs bag,
Cubic feet in 50 lbs bag = 50/133 = 0.375 cubic foot
Adding the found value in the final formula to count required bags,
Number of concrete bags needed in 50lbs size = 1/0.375 = 2.66 bags
Therefore, there are 2.66 concrete bags of 50 lbs size in one cubic foot.
How Many 60lbs Concrete Bags Are In A Cubic Foot?
If you want to find out the required number of 60 lbs of concrete bags for one cubic foot, you can calculate it by any of the two methods discussed above.
Method 1 – Apply the formula of concrete bag count as we have the required data.
Count of 60 lbs Concrete Bags in cubic feet = 133/60 = 2.21 concrete bags
Method 2 – As per this method, we do not have the value of cubic feet in a 60 lbs bag yet; let us find out.
Cubic feet in 60 lbs = 60/133 = 0.451 cubic feet.
Number Of 60 lbs Concrete bags Needed = 1/0.451 = 2.21 bags
So, you will observe that 2.21 concrete bags of 60 lbs size are there in one cubic foot.
How Many 80 lbs Concrete Bags are Needed In Cubic Feet?
Using two methods, let’s find out the number of 80 lbs of concrete bags needed in one cubic foot.
Method 1 – Add the data in the formula for evaluation.
The number of 80 lbs. concrete bags needed in one cubic foot = 133/80 = 1.66 concrete bags.
Method 2 – Calculate the cubic foot in 80 lbs concrete bag.
Cubic feet in 80 lbs concrete bag = 80/133 = 0.601 cubic feet
Adding this to the formula of counting bags,
The number of 80lbs concrete bags in a cubic foot = 1/0.601 = 1.66 concrete bags
Hence, there are 1.66 concrete bags of 80 lbs in one cubic foot.
How Many 90 lbs Concrete Bags Are In A Cubic Foot?
Using two methods, you will find the result below.
Method 1 – Calculate the bags count directly by formula,
Number of 90 lbs concrete bags in a cubic foot = 133/90 = 1.47 bags
Method 2 – Finding the cubic feet in 90 lbs is the first step,
Cubic feet in 90 lbs concrete bag = 90/133 = 0.676 cubic feet
Now, adding the values in the formula of counting bags is the last step,
Number of 90 lbs concrete bags in a cubic foot = 1/0.676 = 1.47 concrete bags
Therefore, there are 1.47 concrete bags of 90 lbs in a cubic foot.
In short, there are 3.32 concrete bags of 40 lbs, 2.66 bags of 50 lbs, 2.21 bags of 60 lbs, 1.66 concrete bags of 80 lbs, and 1.47 bags of 90 lbs in a cubic foot.