Enter the area and the thickness into the calculator to determine the concrete volume needed (e.g., in cubic yards). This calculator helps estimate the volume required for a concrete slab or similar projects. Note: cement is only one ingredient in concrete; the amount of cement (bags) required depends on the mix design or bag yield.

Concrete Volume (Area & Thickness) Calculator

Enter any 2 values to calculate the missing variable

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Concrete Volume Formula (from Area & Thickness)

The following formula is used to calculate the volume of concrete needed for a slab from its area and thickness.

V = A * (T / 12) / 27

Variables:

  • V is the concrete volume needed (cubic yards)
  • A is the area (square feet)
  • T is the thickness (inches)

To calculate the volume of concrete, multiply the area by the thickness (converted to feet by dividing by 12) to get cubic feet, then divide by 27 to convert cubic feet to cubic yards.

What is “Cement Per Square Foot”?

In many construction and DIY contexts, people informally say “cement per square foot” when they actually mean concrete volume per square foot (a volume based on area and thickness). From area and thickness alone, you can calculate the volume of concrete required for a slab. Calculating the amount of cement specifically requires additional information such as the concrete mix design (cement content) or the yield of a bagged concrete product.

How to Calculate Concrete Volume (from Area & Thickness)

The following steps outline how to calculate the volume of concrete needed.

  1. First, determine the area to be covered (A) in square feet.
  2. Next, determine the desired thickness (T) in inches.
  3. Use the formula from above: V = A * (T / 12) / 27.
  4. Finally, calculate the concrete volume (V) in cubic yards.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem :

Use the following variables as an example problem to test your knowledge.

Area (A) = 200 square feet

Thickness (T) = 4 inches