Enter the depth, width and length of her concrete slab to calculation the variety of cubic yards and also concrete bags needed to finish your project.

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Use this complimentary concrete calculator to determine exactly how much concrete you need. Knowing exactly how much concrete is essential for a job is extremely important. Learn how to appropriately calculate how much concrete mix girlfriend will need for your job.


What equation must I use to uncover out exactly how much concrete ns need?

How to calculation concrete:

Determine just how thick you desire the concreteMeasure the length and also width that you’d favor to coverMultiply the length by the width to determine square footageConvert the thickness native inches come feetMultiply the thickness in feet by the square clip to determine cubic feetConvert cubic feet to cubic yards by multiply by .037

Here’s what the mathematics looks like for a 10’ through 10’ concrete patio:

10 x 10 = 100 square feet4 ÷ 12 = .33100 x .33 = 33 cubic feet33 x .037 = 1.22 cubic yards

Essentially girlfriend are resolving for volume and then convert to cubic yards. Because that concrete, the formula for volume is as follows: size x broad x thickness.

To determine how numerous bags the concrete you will need, division the full cubic yards necessary by the yield.

Use the adhering to yields per each bag size:

40 pound bag yields .011 cubic yards60 lb bag yields .017 cubic yards80 lb bag yields .022 cubic yards


Should ns order concrete through the garden from a all set mix agency or just use bags?

Larger work such as driveways are easier to complete when notified concrete by the yard, fairly than trying to mix bag ~ bag by hand. For smaller sized jobs, prefer a walkway, usual patio or footings, you have to calculate the variety of concrete bags instead.

Bagged concrete is appropriate for:

Pouring little slabs for sidewalks or patiosSetting articles for fences or mailboxesMaking repair to structure walls, walkways or stepsPouring tiny curbs, steps, or rampsFootings because that decks, pergolas, walls and more

If you’re purchasing bagged concrete you may be able to have the delivered, but if that is just a few bags you’ll be responsible for carrying it yourself. You’ll also need additional equipment for mixing the concrete. A rented mixer have the right to be really helpful, yet a wheelbarrow works for simply a couple of bags.

Ready blended concrete through the garden is great for:

Large patios, driveways, pool decks and also moreFoundation slabs for a houseParking lots or advertisement sidewalks

If she planning to order concrete from a ready mix supplier, they’ll require to recognize how plenty of yards the concrete come deliver. Countless ready mix service providers will have a minimum stimulate of 1 yard, and also will fee shortage fees as soon as ordering partial batches. The mean truck holds between 9 and also 11 yards total. If your project requires an ext concrete, many trucks will be necessary.


Calculating the quantity of concrete required for slabs (including weird shapes)

Rule of thumb: add 1/4" to the thickness of your slab for her slab concrete budget. This suspect you have the project evenly graded to the appropriate depth, and the grade is fine compacted.

If you check your grade and also one spot is 4", some spots are 4.5" come 5"-the ideal solution because that both the job quality and your concrete budget is to deal with the grade.

Odd shapes: change odd shapes into rectangles and also odd forms are suddenly basic to figure.

Figure driveway 14" x 20" and also your estimate will certainly be good. Right here is why: The driveway is 16" in ~ the top and also 12" at the bottom. Through the center the width averages 14".

Calculating the lot of concrete essential for footings

Footings will hardly ever follow the drawing exactly. In rocky floor the footings might collapse when big rocks are excavated

This was supposed to be a 12"*12" footing, but note how the left side of the footing has collapsed. Calculation the true width.

The excavator may have dug too deep, or the may have actually rained and footings essential to it is in dug out deeper to reach firm soil. So it is essential to examine a selection of clues on her footing and also get an average size. Then use the calculator to number the lot of concrete needed.

House slabs on grade that are 8" the end of grade through a 4" slab also have several of the footing above the class too.

This 12" x 12" footing demands to be calculated 12" x 16" for this reason the footing is figured to go above grade to with the 4" slab thickness.

Estimating concrete steps

Steps it seems to be ~ tricky come calculate however are not. If there room three steps leading approximately a porch:

Use the slab calculator to figure the concrete essential for the porch surface.Use the footing calculator to calculate the sides of the porch and also the steps

Here is an example:

This porch has actually 9 sq. Feet of porch surface, so enter in the slab calculator 4" thickness by 3" broad by 3" length. This totals .11 cubic yards.

The porch also has 9 straight feet the 6" step. So enter in the footing calculator, 6" depth by 12" width (always figure steps with a 12" width) by 9" length. This totals .17 cubic yards.

The complete concrete required for the 3" by 3" porch will certainly be .28 cubic yards. (.11 + .17 cubic yards = .28 cubic yards)

Repeat this for added layers that steps.

Calculating the quantity of basic fill

Granite construction has fantastic base to fill calculator on your site. Usage this to number how much product you require for the subgrade.

Using a Margin that Safety: problems Caused by underestimating the quantity of Concrete

Never shot to bespeak the specific amount of needed concrete. Encompass a margin that safety.

A perfectly placed order that concrete will end up the project with a little amount left over. A 20 cubic yard order through 1 cubic garden left end is a an excellent order. A 20 cubic yard order that comes up cubic yard brief is not a great order.

Extra prices of comes up brief of concrete

Overtime for the crewA quick load fee from the prepared mix supplierA cold share can take place (where one to water ended and also another to water began)

Three steps to ordering enough concrete:

Use the concrete calculatorFigure depths and also widths as they have actually been constructed on the site, not simply what the plan say.Add a margin the safety

Rule of thumb for margin the safety:

If your order isOrder this much extra
1-5 cubic yards.5-1 c.y. Extra
6-10 c.y.1 c.y. Extra
11-20 c.y.1-1.5 c.y. Extra

It can be upsetting to end up with any type of extra concrete. Girlfriend are having actually to pay because that this concrete after ~ all. However, realize you are doing your project a business by ordering sufficient concrete - which method you are going to have actually a little concrete left.

Requesting your ready mix supplier to visit her site

After you have chosen a prepared Mix Supplier, have a representative come to your website to give his/her opinion top top the amount required. To compare the number with what you come up with. Discuss any variances through the supplier.

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Your ready mix caterer is invaluable because that checking your see of task conditions, checking your margin the safety, identifying worries you might not have thought of, and informing you of any local problems you have to be conscious of.