Concrete Pour Calculator

About the Concrete Pour Calculator

Calculates concrete volume for different element shapes, slab, footing or cylindrical column, and adds a waste allowance.

How to use this calculator

1. Choose the shape you are pouring, such as a slab, footing, or column.
2. Enter the dimensions in the same units, for example feet or meters.
3. If the tool asks for thickness or depth, measure that part carefully because it changes the volume a lot.
4. Read the result to see the concrete volume, then add a small extra amount if your project needs a waste allowance.

The formula explained

The calculator finds volume, which is the amount of space the concrete will fill. For a slab, it uses length times width times thickness, and for a footing or column it uses the matching shape formula to estimate the concrete needed.

• L = length of the slab or section
• W = width of the slab or section
• T = thickness or depth
• r = radius of a round column or footing
• h = height or depth of the column or footing
• V = volume of concrete

Step by step method

1. Measure the dimensions of the area or form you will pour.
2. Use the shape that matches your project, then multiply the needed dimensions to get volume.
3. Convert the volume to the unit the calculator shows, such as cubic feet or cubic yards, if needed.

Worked example

Problem. You are pouring a rectangular slab that is \(12\) feet long, \(10\) feet wide, and \(4\) inches thick. How much concrete do you need?

1. Convert the thickness to feet, so \(4\) inches is \(\frac{4}{12} = \frac{1}{3}\) foot.
2. Find the volume with \(V = L \times W \times T\), so \(V = 12 \times 10 \times \frac{1}{3} = 40\) cubic feet.
3. Since \(1\) cubic yard is \(27\) cubic feet, the amount is \(\frac{40}{27} \approx 1.48\) cubic yards.

Tips and common mistakes

• Make sure all measurements use the same unit before calculating, because mixed units give wrong results.
• Round up slightly for waste, uneven ground, or small spills, especially on real job sites.

Frequently asked questions