- How to Calculate Cubic Yards of Concrete Needed for a Patio
- How do I Calculate the Fill for a 16 X 8 Concrete Block With Sakrete?
- How to Estimate Concrete Steps
- How to Calculate Concrete Quantities
- How to Calculate the Volume of Dirt Removed
- How to Figure Cubic Yards of Cement
- How to Calculate the Right Amount of Concrete
- How to Calculate Concrete Floor
- How Do I Calculate How Much Dirt I Need to Fill in a Spot of Lawn?

## How to Calculate Cubic Yards of Concrete Needed for a Patio

Patios are an investment that you put into a property. You want the patio to look nice and be stable during weather changes. Before you order concrete, which is a mixture of water, sand, aggregate and cement, you need to know how much concrete is needed. For patios, the concrete should be 3 1/2-to-4 1/2 inches thick to prevent cracking. Using any more than 4 1/2 inches would be a waste of money for a backyard patio.

## Step 1

Use the tape measure to measure the length of the area for the intended patio in feet.

## Step 2

Measure the width of the patio in feet.

## Step 3

Multiply the length by the width, both in feet, by the thickness in inches and divide it by 12 to get the cubic feet you would need. For instance, if the patio length is 5 feet, the width is 6 feet and the thickness is 4 inches, your calculation would be: 5 times 6 times 4 divided by 12, which would equal 10.

## Step 4

Divide the total cubic feet by 27, since there are 27 cubic feet to a yard. In this instance it would be 10 divided by 27 would equal 0.37 cubic yards.

## Step 5

Purchase 0.37 cubic yards of concrete from a supplier. If you are mixing the concrete yourself, you would need 34 40-lb. bags of pre-mix concrete, 23 60-lb. bags of concrete or 17 80-lb. bags of concrete.

## How do I Calculate the Fill for a 16 X 8 Concrete Block With Sakrete?

Multiply the width times the length in feet of the area to fill. For example, a 16'x18' fill space will require you to multiple16 times 8, which equals 128.

Multiply this number by the depth of the concrete project in feet. For example, a 6-inch deep concrete block is 1/2-foot or .50. Multiply 128 times .50 to obtain 64 cubic feet of Sakrete to fill the block.

Divide the cubic feet of the project by the yield per bag of Sakrete. Forty pound bags yield .30 cubic feet each. Divide 64 by .30 to obtain 213.33 bags to fill the area. Round the final number up to the nearest whole number. So, for this example it will take 214 bags of Sakrete to fill a 16 x 8 x 6-inch block.

## How to Estimate Concrete Steps

Find out the length, width and depth of one of the steps you'll be making out of concrete. If your steps are leading up to a porch, for example, the length of the steps will typically be the length of the porch. Find the length in feet but the width and depth in inches. Typically the width of concrete steps is 12 inches.

Multiply your measurements. If you decided you wanted a 3 foot long by 12 inches wide by 10 inches deep step, for example, those numbers multiplied together would be 360 cubic feet of concrete per step. As one cubic yard is 27 cubic feet, divide 360 by 27 and you get 13.3 cubic yards of concrete per step.

Multiply your cubic yards of concrete per step measurement by the number of concrete steps you'll be making. This will give you the total amount of concrete you need to purchase. If each step needs 13.3 cubic feet of concrete and you want five steps, that means you need 66.66 cubic yards of concrete to complete your job.

## How to Calculate Concrete Quantities

Measure the width, length and depth of the concrete project in feet. If the project is a pad, divide the number of inches by 12 to determine the decimal equivalent of the portion of a foot. For example, a 4-inch thick pad would be .3333 of a foot.

Multiply the width by the length by the thickness of the concrete. For example, a pad that is 16 feet long by 12 feet wide by 4 inches deep would be 16 x 12 x .3333 = 63.99 cubic feet in volume.

Determine the cubic yards by dividing the cubic feet by 27. Using the example, 63.99 cubic feet is equal to 2.37 cubic yards.

An 80-pound bag of concrete is approximately .60 cubic feet of concrete. For a small job, you can calculate the number of 80-pound bags of concrete needed for the project by dividing the number of cubic feet of the project by the number of cubic feet in a bag of concrete. Using the example, 63.99 cubic feet needed for the project divided by .60 cubic feet per 80-pound bag of concrete shows that this project requires 106.656 bags of concrete.

## How to Calculate the Volume of Dirt Removed

Measure in inches the length and width of the hole from which you dug out the dirt.

Hold the measuring tape at the top of the hole to determine the depth in inches.

Divide each of the measures by 12 to determine the number of feet for the length, width and depth measurements. For instance, a hole measuring 12 inches long by 24 inches wide by 6 inches deep would equal 1 foot long by 2 feet wide by 0.5 feet deep.

Multiply the length, width and depth of the hole in feet to find the total volume in inches. For the example: 1 foot x 2 feet x 0.5 feet = 1 cubic foot.

Divide the area by 27 to find the volume of the dirt in cubic yards (because 1 cubic yard = 27 cubic feet). For the example, the cubic yards of the hole would equal 1/27 = 0.037 cubic yards.

## How to Figure Cubic Yards of Cement

Determine the total thickness, in inches, of the cement slab to be laid. This depends on the type of slab you're laying, the purpose you're laying it for and your own preferences. Divide this number by 12 to convert it from inches to feet.

Measure the length and width of the area that will contain your cement. Find this information in feet.

Multiply the two measurements (length and width) from Step 2 together. Multiply the product by the depth measurement (in feet) from Step 1. The number you get is the total cubic feet of cement you need for your project.

Divide your Step 3 number by 27. There are 27 cubic feet in 1 cubic yard. The number you get is the cubic yards of cement needed to complete your project. For example, if your dimensions multiplied together gave you 1,000 cubic feet, 1,000 divided by 27 equals 37.04 cubic yards of cement.

## How to Calculate the Right Amount of Concrete

Use a steel tape measure to measure the area of the project. Measure the width and the length of the space. The depth of the slab for your project depends on the use of the slab. For a driveway, for example, you would need 4 to 5 inches depth. For a sidewalk, 3 inches will suffice.

Convert the measurements for length and width into inches.

Multiply the length by the width by the depth. For example, if your area for the slab is 10 feet 6 inches in width by 27 feet 4 1/2 inches in length by 4 inches in depth, then:

10 feet 6 inches = 126 inches 27 feet 4 1/2 inches = 328.5 inches 4 inches = 4 inches

126 x 328.5 x 4 = 165,564 cubic inches

Convert the cubic inches into cubic yards. A cubic yard in inches equals 46,656. (36 x 36 x 36= 46,656) Divide your amount of cubic inches by one cubic yard or 46,656.

165,564 divided by 46656 = 3.55 cubic yards

Purchase slightly more than your calculations indicate. Because of the organic nature of concrete (a mixture of gravel, cement and water), a physical cubic yard of concrete is a close approximation and not an exact measure.

## How to Calculate Concrete Floor

## Step 1

Measure the length, width and depth (thickness) of the desired floor. Typically, a floor is about 4 inches deep, or about .34 feet. If you have a floor that is 10 feet by 10 feet, you would multiply 10 by 10 by .34, for a total volume of 34 feet.

## Step 2

Divide the volume by 27 to determine the cubic yardage. Because concrete is ordered by the cubic yard, you need to convert your volume to that unit of measurement. In the above example, your calculation would be 34 divided by 27, or 1.26 cubic yards of concrete needed to complete the project.

## Step 3

Plan on ordering more concrete than what your calculations yield. In the event of spillage or other mistakes, you may need more material than you had anticipated. For example, you might add 5 percent to your total. In the above example, 1.26 x 1.05 (5 percent) would be 1.32 cubic yards.

## How Do I Calculate How Much Dirt I Need to Fill in a Spot of Lawn?

## Manual Calculation

To manually calculate your soil needs, use the following formula: Length multiplied by width multiplied by depth in feet, divided by 27 equals yardage. Multiply the yardage by 1.2 because you will need extra material for compacting.

For example, let's say you have a spot to be filled that is 4 feet by 3 feet and you want the soil to be 3 inches deep. Three inches is 1/4 of a foot, so you would write this equation: 4 X 3 X 1/4 = 3. Divide this by 27 to get 0.11 cubic yards. To account for compaction, multiply 0.11 by 1.2 to get 0.132. You will need 0.132 cubic yards of soil for your needs.

## Online Calculation

If you have odd-shaped areas to fill, go to www.areamulchandsoils.com for an online calculator that will determine your needs.