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

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Use this complimentary concrete calculator come determine just how much concrete you need. Knowing how much concrete is necessary for a project is extremely important. Learn just how to effectively calculate how much concrete mix girlfriend will need for your job.


What equation must I usage to uncover out just how much concrete i need?

How to calculate concrete:

Determine how thick you want the concreteMeasure the length and also width the you’d favor to coverMultiply the size by the broad to recognize square footageConvert the thickness native inches come feetMultiply the thickness in feet through the square clip to determine cubic feetConvert cubic feet come 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 addressing for volume and then converting to cubic yards. For concrete, the formula for volume is as follows: size x broad x thickness.

To recognize how plenty of bags the concrete you will certainly need, division the total cubic yards needed by the yield.

Use the complying with yields per each bag size:

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


Should ns order concrete by the garden from a ready mix company or just use bags?

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

Bagged concrete is best for:

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

If she purchasing bagged concrete you may be able to have the delivered, yet if the is just a few bags you’ll be responsible for carrying it yourself. You’ll likewise need added equipment for mixing the concrete. A rented mixer deserve to be really helpful, yet a wheelbarrow functions for just a few bags.

Ready mixed concrete by the yard is good for:

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

If you planning to order concrete native a all set mix supplier, they’ll need to know how many yards that concrete come deliver. Countless ready mix suppliers will have actually a minimum stimulate of 1 yard, and also will charge shortage fees once ordering partial batches. The mean truck holds between 9 and also 11 yards total. If your task requires an ext concrete, multiple trucks will certainly be necessary.


Calculating the quantity of concrete necessary for slabs (including odd shapes)

Rule the thumb: include 1/4" to the thickness of her slab for her slab concrete budget. This presume you have actually the project evenly graded come the right depth, and also the class is fine compacted.

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

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

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

Calculating the amount of concrete necessary for footings

Footings will hardly ever follow the drawing exactly. In rocky floor the footings may 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 actually dug also deep, or that may have actually rained and footings required to be dug out deeper to reach firm soil. So that is vital to check a selection of spots on your footing and also get an typical size. Then use the calculator to number the quantity of concrete needed.

House slabs on grade that room 8" the end of grade with a 4" slab also have few of the footing over the great too.

This 12" x 12" footing needs to it is in calculated 12" x 16" therefore the footing is figured to go over grade to reach the 4" slab thickness.

Estimating concrete steps

Steps seem tricky come calculate however are not. If there space three procedures leading approximately a porch:

Use the slab calculator to figure the concrete necessary for the porch surface.Use the footing calculator to calculate the political parties of the porch and the steps

Here is one example:

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

The porch also has 9 direct feet of 6" step. So get in in the footing calculator, 6" depth through 12" broad (always number steps with a 12" width) by 9" length. This totals .17 cubic yards.

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

Repeat this for included layers the steps.

Calculating the lot of base fill

Granite building has wonderful base to fill calculator on your site. Usage this to number how much material you need for the subgrade.

Using a Margin that Safety: troubles Caused by underestimate the lot of Concrete

Never try to bespeak the specific amount of required concrete. Encompass a margin that safety.

A perfectly inserted order that concrete will finish the job with a tiny amount left over. A 20 cubic garden order with 1 cubic garden left over is a great order. A 20 cubic yard order that comes up cubic yard brief is no a good order.

Extra prices of comes up brief of concrete

Overtime for the crewA brief load charge from the all set mix supplierA cold joint can occur (where one to water ended and another to water began)

Three procedures to ordering sufficient concrete:

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

Rule of thumb for margin the safety:

If her 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 finish up with any extra concrete. Girlfriend are having to pay because that this concrete after all. However, realize you room doing your project a company by ordering sufficient concrete - which method you are going to have a small concrete left.

Requesting your all set mix supplier come visit your site

After you have actually chosen a ready Mix Supplier, have actually a representative come to your website to give his/her opinion on the amount required. Compare the figure with what you come up with. Discuss any type of variances through the supplier.

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Your all set mix supplier is invaluable for checking your watch of project conditions, checking your margin the safety, identifying issues you may not have actually thought of, and informing you of any type of local problems you must be aware of.