#### Pro Tip

# Estimating Bagged Concrete Jobs

Working with concrete can create a bit of anxiety, no matter how big or small the job—whether you’re placing a slab, leveling out a space for a patio or setting posts.

The first and most important step for any concrete project is to work out the volume of concrete needed – which isn’t always easy, even for pros who are used to working in cubic yards.

**“****A quick rule of thumb: one pallet of bags is about a cubic yard of concrete.**

Though it actually takes 45 bags of 80-pound mix to hit a cubic yard dead on, this is a great method to get a good initial estimate.

Visualizing how far a cubic yard isn’t always intuitive, but there’s an easy reference point: 9’ x 9’ slab at 4” deep, or about five sidewalk squares.

In other words, 1 cubic yard of concrete placed at 4-inches deep will cover 81 square feet.

**ESTIMATING THE OLD-FASHIONED WAY**

The formula for estimating the volume of concrete in cubic yards needed on a project is straight forward, though it will definitely require a calculator.

Simply multiply the length by the width by the depth of the desired slab in inches, then divide by 1728. The result is the total cubic feet of the slab.

To get to cubic yards, divide that number by 27.

## “It’s always a good idea to add 10% to every estimate.

**ESTIMATING SHORTCUTS**

Another shortcut method requires knowing a little bit about how far a single bag of concrete will go.

## “The trick: one square foot of concrete equals:

## 1x 50# bag

## 0.8x 60# bags *or*

## 0.6x 80# bags

Though this method only works with a 4” slab, it’s a single calculation that also automatically works in the 10% waste factor, making it a great standby.

For example, if you have a 9’ x 9’ slab at 4” deep, you have a total of 81 square feet. If you’re using 80# bags, you multiply the total square footage (81) by 0.6 to get 48.6 bags – a bit on the high side, but in concrete it’s always better to be safe than sorry.

**SKIP THE MATH**

Sakrete has **concrete calculators** for every type of project to make estimating even easier. From new pours to repairs, resurfacing, masonry work and more, there’s a calculator for your job.

## “There’s a concrete calculator for your job.

Just punch in the dimensions of your job, and the calculators will provide the exact number of bags, recommended products, and provide Project Pro Tips guides to help you get the job done right.

**ESTIMATING IRREGULAR POURS**

Not all jobs are easy rectangles. Adding concrete footings to posts or laying an irregularly shaped or curved slab can require meticulous measuring, or make you dust off your old geometry book, which will inevitably slow you down.

## “Solution? The Sakrete App.

The App uses AR spatial technology to measure and scan project sites to quickly calculate the number of concrete bags needed for slab, post, or repair projects – as well as recommending the right product for the job, and connecting you to your local dealer. Nothing easier than that!

**GET THE JOB DONE RIGHT**

Spot-on estimates are just the first step in tackling your next project. For everything else, make sure to check out our **Project Pro Tips Guides** for step-by-step guidance on the most common jobs, and remember to give us a call at 866-SAKRETE with any questions!

## Comments (62)

Now that was great now I can pour my own driveway

Nice

I’m interested in this calculator

Seems really good how do I apply for it

Thanks

How many bags do we need to pour a 10×12 two inch slab?

That’d be about 45 bags…but add 10% to be safe and round up to 50!

Good job

Amount of cement to do 10 foot by 1 foot by 1.5 inches

That’d be 4 bags…but add 1 more for safety!

How many bags of concrete for a 4 foot by 6 foot by 3 inch slab

Sandy, that’s about 14 60# bags…but add 10% and round up to 16 to be safe!

Just wondering how many bags of concrete would I need to fill the insides of 240 8”x8”x16” Blocks?

Roughly 96. Our sister brand, Amerimix, has a great grout calculator for future reference!

How long will an open bag of Sakrete be used?

It’s going to depend on where it was stored and how much moisture is in the air. Most important note: if it’s hardened, it’s no good.

How many 80lb bags for 14×4 @ 3” Deep?

And, do you need to add sand or lime for a driveway pour?

That’d be 24 bags…but always a good idea to add 10% for variance, so round up to 27 bags!

No need to add anything to bagged mixes for ANY application – everything you need to reach stated performance is right in the bag!

Final point…if this 14×4 slab is for a driveway, definitely need to go deeper than 3″. A minimum of 4″, but 5 – 6″ on a driveway is even better!

I have a shed to place 8×15 how many bags of concrete would I need

Jessica, our Concrete Slab Pour calculator can help with that! If the concrete depth is at least 4 inches, you’ll need either 147 40# bags, 98 60# bags, 74 80# bags, or 67 90# bags to get this job done. Knock it out of the park!

How many 80 # bag’s of sakrete do I need for a 2x2x2 footing

Robert,

You’re looking at around 2 80# bags. Always a good idea to add 10% for variance and round to 3 80# bags!

1. How deep (thick) should a concret walkway be?

2. Do I need to put a layer of gravel down underneath, and/or use rebar or wire grate before pouring concrete?

3. Does it need to be scored with a concrete blade every so many feet to prevent surface cracks even if I’m planning on using a stamp to create a “stone” appearance?

Will greatly appreciate your feedback/advice. Thank you.

James, we recommend 4″ on the concrete walkway, but you can get away with a little less if there will only be foot traffic. Rebar is best practice when it comes to pouring a concrete slab and gravel is a big must. See our Concrete Slab Pour guide for any assistance on this project. Yes, make sure you score with the concrete blade every 8′ to 12′. Goodluck!

How many bags will it take to pour a 24”x 24” x 24” pier

Jeff, sounds like a fun job! After using our Slab Pour Calculator , it seems you would need to use 4224 40# bags, 2816 60# bags, 2112 80# bags, or 1921 90# bags of High-Strength Concrete Mix to get the job done. Goodluck!

How many bags of cement do I need for a room 12 x 19 2 inches thick

Elizabeth, you’re looking at about 110 50# bags, 94 60# bags, or 70 80# bags of concrete. Your choice on the bag sizes! Feel free to check out our Sakrete Slab Pour Calculator https://www.sakrete.com/concrete-calculator/slab-pour/.

I am doing a bag mix job .

Adding to an existing side walk . It’s a triangle from sidewalk to driveway. Open on one side to grass. Adding 18”x48” then 18”x72” in 2steps(1 at a time) I’m 81 not in a hurry.😉 How many 40# bags for each step of the project? Thanks you

Willis, good on you to take on this project! Assuming you’ll be pouring 4-inch sidewalk slabs, you would need at least 8 40# bags of High-Strength Concrete Mix for the first slab and 11 40# bags of High-Strength Concrete Mix for this. Reach out to the professionals at 866-SAKRETE if you have any other questions. Good luck!

Doing a 12’x13’ 3” thick slab

How many 60# bags do I Need or how many 80# bags

Rick,

You are looking at roughly 96 60# bags or 72 80# bags for this job. Check out our Slab Pour Calculator for future help!

14 x 36 sonatube sitting on top of 28 bigfoot…how many bags of 60 lb will I need. I came up with 16 bags ????? For bigfoot and tube

Joan, looks like you’re right on the money with this estimate! Reach out to the team at 866-SAKRETE in case you have any follow up questions.

How many 80 pd bags for 16″ x7″ x336″

Paul, you’re looking at roughly 42 80# bags for a pour like this. Hope this helps!

it helped tank you

It’s our pleasure!

I have a paver patio 12’9″ x 21’6″x 1 3/4″ and a 1/4″ between the pavers.

How many bags will I need to re-point/grout the pavers?

I have been trying to find a good calculator but not successful.

Peter, our sister brand Techniseal’s EZ Sand gives roughly 45-55 sq. ft. per bucket. 7 buckets of product should do you right!

I want a 10×18 slab cement on one side and a 8x10on the other size my contractors said that I would need 40 bags and 30 rebars 2×4 this don’t sign right

Martha, I can help you out with the concrete! Assuming that this is a standard residential concrete slab, it’ll need to be at least 4″ in thickness. Taking that into consideration, you’ll need at least 318 40# bags, or 213 60# bags, or 160 80# bags, or 145 90# bags of high-strength concrete with an added 10% for safety! Consult a professional contractor to help with calculating the amount of lumber and rebar you would need to complete the job. Best of luck!

I have 1000 square feet of 2” cut stone using 50 lb sakrete to install.

How to calculate amount of coverage using 2 inch cut stone using 50 lb sakrete stone veneer

Richard, you’re looking at around 141 50# bags of Stone Veneer Mortar Mix to get you through a project like this. Hope that helps!

It’,s Nice to know that 45 bags cover a yard.

We love educating our audience! Check out Sakrete’s Slab Pour calculator if it brings you any value!

would like to know how many bags of 50 pound of sakrete to do a 9 ‘ x 7’ x 7″ height please? thank you!

Sharon, certainly! If you are using Sakrete High-Strength Concrete Mix, you would need either 135 40# bags, 90 60# bags, 68 80# bags, or 62 90# bags. That’s including the 10% for assurance! Feel free to use our Slab Pour calculator for any other pour in the future.

How namy yard of concrete do I need for a 70feetx26feetx 4inch slap

Johnson, with the knowledge that 45 bags of our 80# High-Strength Concrete bags are equal to one yard – you are looking at roughly 25 yards of bagged concrete. Check out our Slab Pour calculator to learn more!

How many yards is length 20 ft by 7 feet by 4 in thick

John, you are looking at approximately 2 yards of concrete for that setup. Check out our Estimating Bagged Concrete Jobs Pro Tip for more info on how to estimate your projects. Hope that helps!

How many bags of sackcrete do I need for..4in deep×4w×5l

Tony, for a slab pour using Sakrete’s High-Strength Concrete Mix, you would need either 25 40# bags, 17 60# bags, 13 80# bags, or 12 90# bags. That includes the added 10% for good measure. Be sure to check out our Slab Pour Calculator to estimate future projects. Good luck!

A repair on a sidewalk 43” long 20” wide and 4” deep how many bags needed 80 lbs bags ??

Richard, if you were referring to a concrete pour using 80# bags of concrete, around 6 bags of High-Strength Concrete Mix would be needed. That was estimated using our Slab Pour Calculator. If indeed you require a concrete slab repair, look at using 17 – 20# or 7 – 50# bags of our Pro-Mix All-Purpose Cement Mix to help get the job done. That estimation was found using our Slab Repair Calculator. Check out our Sakrete Project Guides for more assistance. You got this!

I absolutely love these hints! By the way, I’m not very familiar with inches. It would be incredibly helpful for European viewers if you could include centimeters in your future posts. You might consider using converters like https://cm-to-inch.com

Alred, thanks for checking out our Pro Tips! We’ll keep this in mind with any future tips that will come out. If you have any questions, do not hesitate to reach out to our support team at 866-SAKRETE!

How many bags of concrete does it take for 10*10 long, 24*24 deep

Elizabeth, thanks for reaching out! Unfortunately, we’ll need more information to determine the kind of project you’re working on. Please reach out to our technical support team at 866-725-7383.

Is there a calculation wheel or a small pocket type book for quick calculations on the go that I can purchase.

Randy, feel free to use our Concrete Calculators to help get your next job estimates done!