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#1




Concrete Cubic Yard to Bagged Sakrete
I work in the fence industry and many times I need to figure out how many bags of concrete I'll need instead of readymix truck pours.
I have a simple calculator I use in Excel, the formula is below, the cells it refers to is number of holes, depth and diameter and it outputs cubic yards needed for the job. I carry this with me on my PDA as well but I found that it is critical for me to find a simple way of calculating 60 and 80 pound bags as well at the same time. I have found plenty of online calculators such as this one which is awesome: www,decks.com/calculators/concrete.aspx but I really need to know the math behind it Can anyone help me out with this? Thanks in advance for any help. =(B3/12*0.5)^2*(3.14)*(D3/12)*(A3)/27 Holes, Dia., Depth, C.Y. Needed, 60#, 80#, $ Per C.Y., Extended 
#2




Re: Concrete Cubic Yard to Bagged Sakrete
That page uses server side scripting so the source is not available to view, so I cannot tell you the math behind that.
I'm sure we can figure out what you need though. You have cubic yards, and need to know how many bags you need. I used that page to enter a square footing 3'x3'x3', which is 1 cubic yard, and it returned that I needed: 60 pound bags = 54 80 pound bags = 40.5 So you just need to add additional cells to your Excel sheet and make it like: cubic yards * 54 = 60 pound bags cubic yards * 40.5 = 80 pound bags 
#3




Re: Concrete Cubic Yard to Bagged Sakrete
Careful, I'm a huge, hairy man that just might kiss you :P
Thanks for the help friend, excellent site you got going here. 
#4




Re: Concrete Cubic Yard to Bagged Sakrete
The volume of cylinder, which is essentially what your hole is, goes as follows:
V = pi X D^2/4 X Depth Where: pi is a constant, which is equal to about 3.14 D = Diameter of the hole volume equals pi X Diameter squared divided by four times the depth Make sure inches are in decimal form, which is done by dividing the # of inches by 12. The solution will be in cubic feet. Multiply this number by the number of holes and this will be the total volume of concrete needed. There are 0.6 cubic feet in an 80lb bag of concrete and 0.45 CF in a 60 lb bag. So take the total volume of concrete needed and divide by 0.6 or 0.45 depending on which size bag is to be used. Its really not all that difficult for example. I have 10 holes that are 1.5' wide by 2.5' deep. 3.14 X (1.5 X 1.5) / 4 X 2.5 = 3.14 X 2.25 / 4 X 2.5 = 4.42cf 4.42 CF X 10 holes = 40.2 cf total of concrete required 40.2/.6 = 67 bags of 80lb concrete TKOBY 
#5




Re: Concrete Cubic Yard to Bagged Sakrete
Calculators have been created to help assist in this:
sakrete.com/products/calculators.cfm 
#6




Re: Concrete Cubic Yard to Bagged Sakrete
how many bags of 60#sakrete to ndo a side walk thats 4' wide x 39' long x 4" deep.

#7




Re: Concrete Cubic Yard to Bagged Sakrete
Quote:
4 ft x 39 ft x 1/3 ft = 52 ft³ An 80 lb bag is 0.6 ft³: 52 ft³/0.6 ft³ = 87 bags 54 ft³ = 2 yd³, you might be better off getting 2 cubic yards delivered mixed. 
#8




Re: Concrete Cubic Yard to Bagged Sakrete
CUBIC INCHES OF FINISHED CONCRETE FOR ONE BAG OF 60# SACRETE = 8415 CU IN PER BAG ? The correct answer should be on the bag.
Last edited by JohnS; 09112011 at 02:48 AM. 
#9




Re: Concrete Cubic Yard to Bagged Sakrete
A 60 lb bag makes up 0.45 ft³ or about 778 in³.

#10




Re: Concrete Cubic Yard to Bagged Sakrete
How many 80 lb bags to make 1.5 yards?

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