Use this free concrete calculator to calculate the amount of concrete required for any construction project.
CONCRETE CALCULATOR FORMAT
Concrete is calculated using the following method:
- How to determine the thickness of concrete
- Calculate the width and length of the area to be covered
- Square footage is calculated by multiplying the length by the width
- Change the thickness of inches to feet
- To calculate cubic feet, multiply the thickness in feet by the square footage.
- Multiplying 037 by the cubic yard measurement will convert cubic feet into cubic yards.
The calculation for a concrete patio measuring 10′ by10′ will be:
- 10 x 10 = a 100-square-foot area
- 4 / 12 = .33
- 100 x 0.33 = 33 cubic feet
- 33 x .037 = 1.22 cubic yards
The volume is calculated first and then converted to cubic yards. The formula for concrete volume is:
Length x width
Divide the total cubic yards by the yield to calculate the number of bags required for concrete.
Use the following yields for each bag size.
- 40-pound bag yields 0.01 cubic yards
- 60-pound bag delivers 0.017 cubic yards
- The 80-pound bag delivers 0.022 cubic yards
Calculating the concrete needed for odd-shaped slabs
Rule-of-Thumb: Add 1/4″ to your slab thickness for your slab concrete budget. The assumption is that the slab is graded evenly to the same depth and is compacted well.
If you find that some spots on your grade are 4″ and others are 4.5″ – 5″, the best solution is to fix your rate. This will improve the quality of your job and also your budget.
Odd shapes are easily calculated by converting irregular shapes to rectangles.
The estimate will be accurate if you use the 14′ 20′ figure since the driveway measures 16′ in the middle and 12′ in the bottom. The width is 14′ on average through the middle.
Calculating how much concrete is needed for footings
The footings are rarely based exactly on the drawings. When big rocks are removed from rocky soil, the feet can fall.
It may be that the excavator dug deep or if it rained, and the footings needed to be dug deeper to achieve solidity. It is important to keep an average size and examine the different spots. Calculate the required amount of concrete using the calculator.
Some of the footings are also the grade in-house slabs that are 8″ off-grade.
The footing for a 12″x 12″ slab should be calculated as 12″x 16″. This is because the floor will go over grade in order to achieve the 4″ thickness.