Concrete Calculator

Estimate the total weight of concrete you need for a job based on the total volume of the area. Enter length, width, and height.

Calculate how much concrete you need before  project starts can decrease waste and save you money.  The following equation is how this calculator solves for the number of premix bags your project will need.

  1. Determine the thickness of the slab
  2. Determine the length and width of the slab
  3. Calculate the total volume of the slap 
  4. Determine how much volume each bag yields 
  5. Divide the total volume by the volume yielded from each bag. 

Use the following values for the total volume yielded from each bag. 

  • 40 pound bag will yield approximately .011 cubic yards
  • 60 pound bag will yield approximately .017 cubic yards
  • 80 pound bag will yield approximately .022 cubic yards
  • 100 pound bag will yield approximately .028 cubic yards
  • 200 pound bag will yield approximately .056 cubic yards

Ready Mix Concrete vs Bagged Concrete 

If you’ve played around with the calculator above, you can tell that the number of premix bags can skyrocket for larger jobs. For this reason you should only use bagged concrete for smaller jobs such as porches or small sidewalks. 

Otherwise you should go with ready mix concrete, or in other words, concrete delivered by a supplier that’s ready to be laid down. Typically these trucks that deliver ready made concrete can carry between 9-11 cubic yards. This is a significant jump from the amount that premix bags yield. 

We suggest that anything over 2 cubic yards should be done with ready mix concrete. Otherwise you will be slugging around hundreds of pounds of concrete for your job. Invest the money and save your back. 

Cost of running short on concrete

One thing to keep in mind when calculating the concrete needed for a job, is to never order the exact amount required for a job. The general rule of thump is that an extra 5% should be purchased for a job in order to account for errors while pouring or things like cold joints. If you come up short of concrete you can start to incur large costs especially if ordered by the truck load

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