Then, you can calculate the amount of concrete you need for the job you want. How to do? Enter the depth, width and length of your concrete slab, footing and the diameter of column to calculate the number of cubic yards and concrete bags needed to complete your project.

- Determine how thick you want the concrete
- Measure the length and width that you’d like to cover
- Multiply the length by the width to determine square footage
- Convert the thickness from inches to feet
- Multiply the thickness in feet by the square footage to determine cubic feet
- Convert cubic feet to cubic yards by multiplying by .037

- 10 x 10 = 100 square feet
- 4 ÷ 12 = .33
- 100 x .33 = 33 cubic feet
- 33 x .037 = 1.22 cubic yards

Essentially you are solving for volume and then converting to cubic yards. For concrete, the formula for volume is as follows: length x width x thickness.

To determine how many bags of concrete you will need, divide the total cubic yards needed by the yield.

- 40 pound bag yields .011 cubic yards
- 60 pound bag yields .017 cubic yards
- 80 pound bag yields .022 cubic yards

Patio size:
Typically the price per square foot goes down as the patio gets bigger. Alternatively, for small patios, some contractors charge a minimum total rather than a per square foot price.

Property condition:
If you need grading, demolition or other site work, the price will go up. Also, if your property can’t be accessed with the necessary equipment, requiring a pump or additional labor, costs will rise.