We’ll cover the process for estimating concrete in detail below, but you can also use the calculator above to simplify the process. For slabs the thickness can be substituted for the height measurement. Our online concrete calculator is a powerful tool that you can use to help ensure your next landscaping project goes smoothly. For more complex shapes check out our volume calculator. Much of the work to pour concrete is done before the truck even arrives at the project.

Real-time graphics. Installing a new concrete driveway usually costs between $4,000 and$8,500. We know this can be tricky when working with concrete, especially when estimating. On a scale of 1 to 5, the time required is 3/5. Circular slab with price per unit of volume, 4 curbs with price per unit volume and 50 lb bags of concrete. I want to figure out how many bags of 40 lb concrete I need to do this. Enter the size of the slab you want to build in square feet. The amount of overage you plan for will vary based on your quantity but plan for at least 10% overage to accommodate spillage, settling, and grading inconsistencies. Let’s say I need to construct a square concrete slab that is 12 feet wide (an area of 144 square feet) and 4 inches deep. Measure the length, width, and height of the slab, footing, or column.

To determine how many bags of concrete you will need, divide the total cubic yards needed by the yield. Using the measurements provided, our calculator first works out the volume of the required concrete mix using the formulae given below.

Typically, there are fees for delivery, weekend service, small loads, and overtime for long unloading times. For our next example, let’s say we need to construct 4 curbs with the following measurements: The calculator would first work out the total volume of the 4 curbs: $$Curb\,volume = Curb\,depth \times Curb\,height \times Length = 3\,in \times 4\,in \times 10\,ft = 0.8333\,ft^3$$, $$Gutter\,volume = (Gutter\,width + Curb\,depth) \times Flag\,thickness \times Length = (10\,in + 3\,in) \times 3\,in \times 10\,ft = 2.7083\,ft^3$$, $$Volume = Curb\,volume + Gutter\,volume = 0.8333\,ft^3 + 2.7083\,ft^3 = 3.54\,ft^3$$, $$Total\,volume = Volume \times Quantity = 3.54\,ft^3 \times 4 = 14.167\,ft^3$$. Get hassle-free estimates from local concrete professionals for your concrete project. The site must be measured and laid out. On average it will take 90 40lb bags, 60 60lb bags, or 45 80lb bags to fill one cubic yard of concrete.

Before we begin please note: The number of bags required must be rounded up, otherwise you’ll be left without sufficient concrete. Learn what affects the price before planning your new driveway project. The ready mix concrete calculator does the following calculations: $$Volume = \pi \times (Outer\,radius^2 – Inner\,radius^2) \times Height = \pi \times (5\,ft^2 – 4.5\,ft^2) \times 5\,ft = 74.6\,ft^3$$, $$Weight = Volume \times 145\,lb/ft^3 = 74.6\,ft^3 \times 145 = 10819\,lb$$, $$Bags = {Weight \over 40\,lb} = {10819\,lb \over 40\,lb} = 270.4 \rightarrow 271\,bags$$, $$Cost = Volume \times Price\,per\,unit\,of\,volume = 74.6\,ft^3 \times 108\,/yd^3 = 298.45$$, We imagine you are wondering what happens if you want to use concrete bags weighing different amounts. The outer diameter is 10 ft and the inner diameter is 9 ft. Order additional concrete for your project. yds3 = (π × radius ft × radius ft × height ft) / 27. If your hole is 36” deep and 10” wide, the calculation is 3.14 x 5 x 5 x 36 ÷ 1728.

On average it will take 90 40lb bags, 60 60lb bags, or 45 80lb bags to fill one cubic yard of concrete. Don’t forget, it can be helpful to purchase slightly more concrete than the volume the estimator calculates to allow for spillage and alterations in slab depth. Calculated at 2160 kg per 1m³ - Allow extra for waste A concrete slab 1000 mm X 1000 mm at a depth of 100 mm, has a volume of 0.1 m³ = 10.8 x 20 kg bags 11 Bags Welcome to the concrete calculator. Rebar or fiber or steel mesh should be installed to reinforce the concrete and to prevent cracking in the future. Call your supplier and understand these costs ahead of time and plan accordingly. Find Qualified Concrete Professionals in Your Area.

This gives you 1.6 cubic feet. Simply select from the multiple options in the drop down menu to select a different weight. Calculated results will reflect how many bags are needed for Block and Brick. It will help you calculate the number of bags of concrete required for your path, slab or post holes. Our calculator can do all the conversions for you, meaning you don’t have to. For instance, if you are measuring a slab that is not a rectangle or circle, break it into different sections and measure the yards needed for each section first, then add them together. Pre-mix bags usually range from $2.50 to$7, making them a cost effective choice for small projects.

Both concrete calculators make an allowance for the fact that ballast etc losses volume when mixed to make concrete. Refer to table below that shows the coverage of different sizes of pre-mix bags.

Consider that for smaller projects there will likely be additional fees for ready-mix, such as delivery or short-load fees.. Estimate how many pre-mixed bags needed for smaller projects, if it may not be practical to order a truckload of concrete and pre-mixed bags make the most sense. Mixing bags on-site can become difficult if you’re pouring a large slab or have many footings. So now that we know the volume the second step is to calculate … Also, if you know the price per unit volume, then our calculator can work out the total cost: $$Cost = Total\,volume \times Price\,per\,unit\,of\,volume$$. For each measurement of length, you are able to work in metric units (feet, yards, inches) or imperial units (centimeters, meters). Use the following yields per each bag size: 40 pound bag yields .011 …

Add the volume for each rectangle to find the total volume.

Thank you for using the concrete calculator. If your project is small, you can use pre-mixed bags of concrete. (all yields are approximate and do not allow for uneven substrate, waste, etc.) Use our masonry calculators and expert-written articles to plan your next concrete or masonry project. Well, our calculator can figure this out for you as well.

On a scale of 1 to 5, the cost level is 2/5. Project cost: low cost. You can purchase pre-mix bags from your local home center. Completely settling in place might take several years, depending on climate and other conditions. If you need to construct multiple concrete slabs/columns, etc., then our calculator can work out the total volume required: $$Total\,volume = Volume \times Quantity$$.

When you start any construction project, it’s important that you have an idea of how much material you are likely to need.

You’ll notice that we do this with all our examples (but the calculator does this for you!). Concrete is a composite material used for all kinds of construction projects, especially where high compressive strength is required. In our final example, let’s say we have 3 steps leading up to a platform (for a total of 4 steps), with the following measurements: The calculator first works out the volume under the platform: $$Volume\,under\,platform = Platform\,depth \times Rise × Width \times Number\,of\,steps = 8 \times 7 \times 9 \times 4 = 2016\,yd^3$$.