Concrete Calculator: Slab & Volume Estimation

How to Calculate Concrete Volume

The process of calculating concrete volume varies depending on the shape of your form. Here’s a breakdown of how our concrete volume calculator determines concrete volume.

Concrete Volume Formula

The concrete volume formula is simple:

  • Length x Width x Thickness = Concrete volume

After calculating the total cubic feet using this formula, divide the result by 27 to convert it to cubic yards.

Calculating Concrete for Slabs

The formula for calculating concrete volume for slabs is the same as the standard concrete volume formula:

  • Length x Width x Thickness = Concrete volume

Calculating Concrete for Footings

You can use the same formula for calculating the volume of concrete footings:

  • Length x Width x Thickness = Concrete volume (You may want to break up L-shaped footings into two squares or rectangles to make it easier to find the volume.)

Calculating Concrete for Columns

You need to use a slightly different formula to calculate concrete for columns:

  • Diameter x Height = Concrete volume

Common Concrete Applications

Our concrete volume calculator makes it easy to figure out how much concrete you need for various projects, including:

  • Buildings and foundations
  • Countertops
  • Driveways
  • Fire pits
  • Garden hardscapes
  • Patios
  • Sidewalks

Concrete Estimation Tips

There are a few simple tips you can use to make your next concrete project easier:

  • Add 1/4” to the thickness of concrete slabs
  • Order slightly more concrete than you think you need
  • Divide odd shapes into rectangles to make calculations easier
  • Use a footing calculator to calculate the volume of concrete steps

Shop Concrete Supplies

Shop concrete tools and supplies at White Cap Canada, including concrete equipment, concrete anchors, and more.


Concrete Calculator FAQs

The amount of concrete you need for a slab depends on the length, width, and thickness of the slab. You can input the dimensions of your concrete slab into our concrete calculator to find the total volume of the slab. Once you have the volume of the slab in square feet, divide that number by 27 to figure out how many cubic yards of concrete you need.

You can calculate concrete volume using a simple formula:


  • Length x Width x Thickness = Concrete volume


This formula works for various types of concrete projects, including patios, driveways, and other slabs. You can divide more complex shapes like L-shaped footings into separate rectangles, then find the volume of each rectangle and add the two numbers together.

Before you use our concrete calculator, you’ll need to know the length, width, and thickness of your concrete slab. If you’re pouring a concrete column, you’ll need to know the height and diameter of the column. Our concrete calculator automatically calculates the number of bags you need for your project.

Yes, White Cap Canada’s concrete calculator supports metric and imperial measurements. You can change the unit of measurement using the dropdown menu to the right of the fields where you input the dimensions of your concrete slab or column.

A general rule of thumb is to order 10% more concrete than you think you need for a project. Ordering extra concrete isn’t just about accounting for inaccurate measurements and miscalculations, it also helps you account for factors like spillage and form deflection. You can also add 1/4” to the thickness of your slab to account for overages.

The number of bags of concrete you need for a project can vary widely, with numbers ranging from one or two bags to hundreds of bags depending on the project. You can use our concrete calculator to figure out exactly how many bags of concrete to purchase for your next project.