Concrete Calculator

Concrete volume calculator calculates concrete volume for the square column, wall, footing, round column, stair, curb and gutter. Also, use the calculator to estimate the pre-mix concrete needed for your project.

How Much Concrete Do I Need?

To calculate how much concrete of walls, square slab or footing you need. First measure its width, length, and depth.

Simply multiply the width by length and thickness(or depth), also, if there are multiple quantities, enter the quantities number to get the total volume of concrete.

Round Column Concrete Formula

To calculate the concrete volume of a round slab column, measure its base or diameter(R) and height(h), and then multiply the square of half of R by π which is
V=πr²xH (while r=R/2).

For example, if the round slab's base is 3 feet, the height is 4 feet. the calculation is below:
πx1.5²x4=3.1415x1.5x1.5x4 =28.27. (the r is 3/2=1.5)

How to Calculate Concrete for Curb and Gutter?

To calculate the concrete curb and gutter,  need to measure its curb depth, curb height, gutter width, flag thickness, and length. We need to divide it into two parts for easy calculation.

1. Calculate the gutter part by multiplying the gutter width by flag thickness and length.

2. Calculate the curb part, that is curb depth multiplied by length, and height.
(the curb height plus flag thickness will be the right height for calculation).

3. Add two volumes together.

Calculate Concrete Stairs

To calculate concrete steps or stairs,  we need to know the total number of steps including the platform. Considering every step are the same size, expect the top platform depth different from other steps, so just need to measure run, rise, and width for one step (stair) and platform depth.

Multiply run, rise, and width, that is the volume of the first steps,
 the second step is two times of first steps,

the third step is three times of first step's volume, and so on. 

The last step is the platform, its volume is calculated as platform depth multiplied by platform rise and width.

For example, if there are 4 steps with a run of 8 inches, a rise of 9 inches, and a width of 20 inches. platform depth of 10 inches.

Volume of step 1: 8x9x20=1400 cubic inches = 0.8333 cubic feet.
volume of step 2: 2x0.833 cubic feet.
volume of step 3: 3x0.833 cubic feet.

platform volume = 10x(9x4)x20=7200 cubic inches =4.17 cubic feet (here:platform rise = step rise x total steps)

the total volume of 3 steps plus platform is
0.833+2x0.833+3x0.833+4.17=9.17 cubic feet.

How Many Bags of Concrete Do I Need?

To calculate how many bags of concrete you need, first, need to calculate the volume of concrete.

Use our different shapes of concrete calculators to get the volume of your project, then choose the 40lbs, 80 lbs, or 60 lbs per bag to get the estimated bags you need.

The standard ready-mix concrete weighs 133.33 lbs per cubic foot, therefore 80 lbs bag of concrete can cover around 0.6 cubic feet, 60 lbs of concrete cover up to 0.45 cubic feet, and 40 lbs cover up to 0.3 cubic feet.

For example, if your project volume is 500 cubic feet, divide 500 by 0.6 cubic feet, 500/0.6≈84 bags of 80 pounds of concrete.