How to figure yards of concrete from square feet

Readymix Concrete Calculator

Use the Readymix Concrete Volume Calculator to calculate the volume of concrete you require for your job. If you are not sure of how to calculate the volume of different shapes, you can use the Common Shape Calculator which will provide you with the appropriate equations.

Frequently Asked Questions  

How much concrete is in a yard?

Concrete volume is measured in cubic yards. When poured on a perfectly level surface, one cubic yard will cover 27 square feet at one foot thick.

How much does a yard of concrete weigh?

A solid, unbroken slab of concrete weighs about two tons (or 4,000 pounds) per cubic yard. Breaking up concrete roughly halves the total weight per cubic yard to about one half ton (or about 2,000 pounds).

How many bags of concrete are in a yard?

To produce one yard of concrete, you’ll need to use about 45 80-pound bags (or 90 40-pound bags). Because of the time and labor required to prepare such a large quantity, it is usually more cost- and time-effective to have ready mix concrete delivered.

Should I buy bagged concrete or have ready mix delivered?

CEMEX specializes in ready mix concrete formulated to your exact specifications and delivered to your job site. Larger jobs can be completed much more easily and efficiently when you order ready mix concrete by the yard. Ready mix concrete is ideal for large patios, driveway renovation, pool decks, home foundation slabs, parking lots, and new sidewalk construction. If you’re just doing some DIY maintenance around your home property, a yard of concrete is going to be far more than you’re able to use. In these cases, it makes more sense to purchase bagged products and mix them yourself. Examples of smaller projects include minor repairs (curbs, sidewalks, stairs, etc.), ramps, small patios, and setting fence posts.

What’s the minimum amount of ready mix concrete I can order?

CEMEX has a minimum order volume of 1cubic yard per delivery.

How much extra should I order?

Ordering the exact amount of concrete, you need for a job is a recipe for disaster. As a general rule, you should add an additional margin of 10 to 15% to your order to account for things like spillage while pouring, uneven subgrades, and other variables. Coming up short on a concrete pour will always be far more expensive than the cost of factoring in extra concrete from the start. The project timeline gets delayed, you have to pay your crew for the additional time spent, and you have to account for the cost of dispatching another truck to the job site – all factors which eat into your budget and hurt your bottom line. The quality of the pour itself is also likely to suffer – time is of the essence when pouring concrete, so you run the risk of having a cold joint occur where the two separate pours do not combine seamlessly. In a worst-case scenario, you may have to tear it all up and start over.

The calculator will estimate the volume of concrete or aggregate needed for your project.


You can calculate how much concrete you need for your construction project using this calculator that works in both US Customary Units (feet and inches) and International System of Units or metric units (meters and centimeters) of measurement.

Most concrete purchases will be made in cubic yards, which equates to 27 cubic feet. For example, a project measuring 10 ft in length by 10 ft in width with a depth of 3.5 in will be just over 1 cubic yard. The equivalent to a single cubic yard in metric measurements would be roughly 0.76 cubic meters.

The output of this calculation should make it simple for you to work out the estimated cost of the concrete materials that you require. For more specific pricing, contact your CEMEX sales representative to discuss.

There’s rarely a perfect pour in any project, so you may consider adding a little extra contingency to your order to account just to be on the safe side. The amount you decide to order will depend on the size and complexity of your site and project. It’s also important to know how this will affect your overall budget.

The concrete calculator should help you get started on the planning phase of your project. Be sure to discuss with your sales rep when you are ready to order your concrete.

To use the calculator:

  • Choose units of measure: English or Metric.
  • Enter the width, length, and thickness of the project.
  • Select whether you are measuring thickness in feet or inches.
  • Click Calculate.

Use this calculator to convert between square feet (ft²) and cubic yards (yd³). A separate cubic yards calculator is available for those with individual width, length and height measurements. For area measurements and conversions you can use our square footage calculator.

Disclaimer: Whilst every effort has been made in building our calculator tools, we are not to be held liable for any damages or monetary losses arising out of or in connection with their use. Full disclaimer.

How to convert square feet to cubic yards

To convert square feet to cubic yards, simply multiply your square footage figure by the height or depth of the area (in feet) to get a volume measurement in cubic feet. Next, divide the total by 27 to get your measurement in cubic yards.

Should your height or depth figure be in inches, simply divide it by 12 to get your feet figure (there are 12 inches in a foot). Also, note that there are 27 cubic feet in a cubic yard.

How to figure yards of concrete from square feet

Formula for cubic yards

Cubic yards = [width × length × height in ft] ÷ 27

Square feet to cubic yards

Cubic yards = [square feet × height in ft] ÷ 27

How to calculate cubic yards

  1. Calculate your square feet area: Width × length
  2. Calculate the volume: Multiply your area figure by the depth/height. This gives you a volume figure in cubic feet
  3. Convert to cubic yards: Divide your cubic feet figure by 27. You now have your answer.

How to convert cubic yards to square feet

To convert cubic yards to square feet, multiply your cubic yards figure by 27 (to get cubic feet) before dividing by the height or depth of the area (in feet).

Converting between cubic yards and square feet requires an extra dimension (commonly height or depth). Once you have this extra measurement, you can incorporate it into your calculation. I've included the formulae for this below.

Note: these formulae assume all measurements are in feet:

Formula for square feet

Square feet = width (ft) × length (ft)

Cubic yards to square feet

Square feet = (cubic yards × 27) ÷ height (ft)

Of course, if you use our calculator at the top of the page, it'll work these calculations out for you. If you need to, you can convert between square feet and cubic feet here.


If you have any problems using our square feet and cubic yards calculator, please contact us.


What is the formula for calculating concrete?

Calculating the volume for concrete requires using three dimensions: length times width (which is area) times the height (thickness) or L x W x H. If you are using feet as your standard unit of measurement, this formula will give you the volume of concrete in cubic feet.

How do I figure out how many yards of concrete I need for a slab?

How do I calculate how much concrete I need for a slab?.
Measure the area in feet..
Multiply length by width, and then by thickness..
Divide the resulting number by 27 to find cubic yards..

How many yards of concrete do I need for a 24x24 x4 slab?

For an approximate idea of how much concrete you need, use the Concrete Volume Calculator below. For example, for a concrete slab that is 24' X 24' X 4”, simply enter 4 in the Thickness/Depth field, 24 in the Width field, and 24 in the Length field. Click “Calculate”. Your answer should be 7.11 yards.

How many yards is a 20x20 slab?

Step 2 :- converting cubic feet into cubic yard:- now converting into cubic yard, you should divide it by 27, because 1 cubic yard = 27 cubic foot, so volume of concrete you needed for 20×20 slab at 4 inch thick in cubic yard = 132/27 = 4.88 cubic yard.