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How Many Yard Of Concrete In A 80 Pound Bag: Calculation
Do you want to know how many cubic feet per 80 pound concrete bag you get? Are you asking how much concrete does 80 lb bag make? A standard 80 pound bag of concrete mix usually makes about 0.6 cubic feet of concrete. This means you get a bit more than half of a cubic foot of concrete from one 80 lb bag. To figure out how many cubic yards from concrete bags this equals, we need to do a simple math step. Since one cubic yard is the same as 27 cubic feet, an 80 lb bag makes about 0.022 cubic yards (0.6 divided by 27). So, one 80 pound bag gives you a very small amount of a cubic yard.
Why Knowing Your Concrete Amount Matters
Working with concrete is a big part of many home projects. You might be setting a fence post. Maybe you want to fix a small crack. You could be pouring a stepping stone. Or maybe a small patio.
When you buy concrete in bags, like an 80 lb bag, it’s important to know how much finished concrete you will get. This amount is called the ‘yield’. The concrete yield 80 lb bag tells you the space the mixed concrete will fill.
Why is this important?
* Save money: You don’t want to buy too many bags. That wastes money.
* Finish your job: You need enough concrete. Running out in the middle of a pour is bad.
* Plan your work: Knowing the amount helps you plan mixing and pouring.
You need to know the volume of concrete bag after you add water. This is different from the dry weight in the bag. The amount of space the mixed concrete fills is what matters for your project size.
Deciphering Bagged Concrete Volume
Concrete comes in different size bags. Common sizes are 40 lb, 50 lb, 60 lb, and 80 lb. Each bag size makes a different amount of mixed concrete.
The 80 lb bag is very popular for many jobs. It’s heavy, but it gives a good amount of concrete for its size. Finding the cubic feet per 80 pound concrete bag is key.
Think of volume like filling a box. A cubic foot is a box 1 foot long, 1 foot wide, and 1 foot tall. An 80 lb bag of concrete mix, when mixed with water the right way, will fill a box that is about 0.6 feet high, 1 foot wide, and 1 foot long. Or any shape that adds up to 0.6 cubic feet.
Most makers of concrete mix bags tell you the rough yield on the bag. It’s usually given in cubic feet. For an 80 lb bag, this is commonly around 0.6 cubic feet. Some mixes might give slightly more or less. Always check the bag if you can.
The Base Number: 80 lb Bag Yield in Cubic Feet
So, the main number to remember for an 80 lb bag is about 0.6 cubic feet. This is the 80 lb concrete yield cubic feet.
This number is not always exact. Why?
* The amount of water you add changes the volume a little. Using too much water makes the concrete weaker and might change the final volume slightly.
* How well you mix it matters.
* The exact mix of sand, gravel, and cement in the bag can vary a tiny bit.
But for planning most home projects, using 0.6 cubic feet per 80 pound concrete bag is a very good number to use. It helps you figure out how many bags you need for a certain area or shape.
Turning Cubic Feet into Cubic Yards
Concrete for bigger jobs is often talked about in cubic yards. A cubic yard is a much larger amount of space.
Imagine that cubic foot box again (1 ft x 1 ft x 1 ft). Now imagine a much bigger box that is 3 feet long, 3 feet wide, and 3 feet tall. This big box is one cubic yard.
How many of the small cubic foot boxes fit inside the big cubic yard box?
* Along the front: 3 boxes
* Going back: 3 rows of boxes
* Going up: 3 layers of boxes
So, the total number of cubic foot boxes that fit is 3 x 3 x 3 = 27.
This means 1 cubic yard = 27 cubic feet.
Now we know:
1. An 80 lb bag gives about 0.6 cubic feet.
2. 1 cubic yard is the same as 27 cubic feet.
To find out how many cubic yards you get from one 80 lb bag, you divide the cubic feet yield by 27.
Calculation:
0.6 cubic feet per bag / 27 cubic feet per cubic yard = 0.0222… cubic yards per bag
So, one 80 lb bag makes a tiny fraction of a cubic yard. About 0.022 cubic yards.
Let’s put that in a simple table:
h4. Volume from One 80 lb Concrete Bag
| Measurement Unit | Approximate Volume |
|---|---|
| Cubic Feet | 0.6 cubic feet |
| Cubic Yards | 0.022 cubic yards |
This shows you clearly that an 80 lb bag does not make much of a cubic yard. You would need many, many bags for one full cubic yard.
Grasping Concrete Coverage Per Bag
Knowing the volume helps you figure out the concrete coverage per bag. This is about how much area a bag will cover at a certain thickness.
Let’s say you want to pour a concrete slab that is 4 inches thick.
First, work in the same units. Let’s use feet.
4 inches needs to be changed to feet. There are 12 inches in a foot.
4 inches / 12 inches per foot = 0.333 feet (or 1/3 foot).
So, you want a slab that is 0.333 feet thick.
One 80 lb bag makes 0.6 cubic feet. This means it fills 0.6 cubic feet of space.
If you spread this 0.6 cubic feet out to a thickness of 0.333 feet, how much area will it cover?
Area = Volume / Thickness
Area = 0.6 cubic feet / 0.333 feet
Area ≈ 1.8 square feet
So, one 80 lb bag can cover about 1.8 square feet at a thickness of 4 inches.
h4. Approximate Coverage for One 80 lb Bag
| Thickness (Inches) | Thickness (Feet) | Approximate Coverage (Square Feet) | Calculation (0.6 cu ft / Thickness in ft) |
|---|---|---|---|
| 1 inch | 0.083 feet | 7.2 sq ft | 0.6 / 0.083 ≈ 7.2 |
| 2 inches | 0.167 feet | 3.6 sq ft | 0.6 / 0.167 ≈ 3.6 |
| 3 inches | 0.25 feet | 2.4 sq ft | 0.6 / 0.25 = 2.4 |
| 4 inches | 0.333 feet | 1.8 sq ft | 0.6 / 0.333 ≈ 1.8 |
| 6 inches | 0.5 feet | 1.2 sq ft | 0.6 / 0.5 = 1.2 |
| 8 inches | 0.667 feet | 0.9 sq ft | 0.6 / 0.667 ≈ 0.9 |
This table helps you see how much area one bag covers based on how thick you make the concrete layer. This is very useful when figuring out how many bags to buy for a flat area like a walkway or slab.
Calculating Concrete Bags Needed for Your Job
Now you know the volume one bag makes. You also know how much area it covers at certain depths. This lets you calculate concrete bags needed for your specific project.
Here are the steps:
1. Figure out the total volume of concrete you need for your project.
2. Use the yield per bag (0.6 cubic feet for an 80 lb bag).
3. Divide the total volume needed by the volume one bag makes.
Step 1: Find Your Project Volume
Most projects are shapes like squares, rectangles, or circles. You need to find the volume of that shape. Volume is usually Length x Width x Height (or Thickness).
It’s easiest to do all your measurements in feet first.
* If you measure in inches, divide by 12 to get feet. (Example: 6 inches = 0.5 feet)
* If you measure in yards, multiply by 3 to get feet. (Example: 1 yard = 3 feet)
Let’s do an example. You want to pour a small concrete pad for an air conditioner.
The pad is 3 feet long.
The pad is 2 feet wide.
The pad is 4 inches thick.
First, change the thickness to feet: 4 inches / 12 = 0.333 feet.
Now, find the total volume in cubic feet:
Volume = Length x Width x Thickness
Volume = 3 feet x 2 feet x 0.333 feet
Volume = 6 x 0.333 cubic feet
Volume ≈ 2 cubic feet
So, you need about 2 cubic feet of concrete.
Step 2: Use the Bag Yield
We know one 80 lb bag makes about 0.6 cubic feet.
Step 3: Divide to Find the Number of Bags
Number of bags = Total Volume Needed / Volume per Bag
Number of bags = 2 cubic feet / 0.6 cubic feet per bag
Number of bags ≈ 3.33 bags
You can’t buy a third of a bag. You always need to round up to the next whole bag.
So, you would need to buy 4 bags of 80 lb concrete.
It’s also a good idea to buy one extra bag. This covers small mistakes, waste, or if your measurements were slightly off. So, maybe buy 5 bags to be safe for this project.
Another Example: A Small Footing
Let’s say you are building a small deck and need a footing.
The footing is a square column shape.
It is 1 foot wide (12 inches).
It is 1 foot deep (12 inches).
It is 2 feet tall (24 inches).
All measurements are already in feet or can be easily changed.
Width = 1 foot
Depth = 1 foot
Height = 2 feet
Volume = Width x Depth x Height
Volume = 1 foot x 1 foot x 2 feet
Volume = 2 cubic feet
This is the same volume as the last example!
Number of bags = Total Volume Needed / Volume per Bag
Number of bags = 2 cubic feet / 0.6 cubic feet per bag
Number of bags ≈ 3.33 bags
Again, round up to 4 bags. Buy 5 to be extra safe.
Working with Cubic Yards for Bigger Projects
What if your project volume is already given in cubic yards? For example, you are told you need 0.5 cubic yards of concrete.
You want to know how many 80 lb bags you need for 0.5 cubic yards.
You have two ways to figure this out:
Method 1: Convert Cubic Yards to Cubic Feet First
- You need 0.5 cubic yards.
- 1 cubic yard = 27 cubic feet.
- Total cubic feet needed = 0.5 yards * 27 cubic feet/yard = 13.5 cubic feet.
Now use the yield per bag in cubic feet:
Number of bags = Total cubic feet needed / Volume per bag in cubic feet
Number of bags = 13.5 cubic feet / 0.6 cubic feet per bag
Number of bags = 22.5 bags
Round up to 23 bags. Buy a few extra (maybe 25 total) just in case.
Method 2: Use the Bag Yield in Cubic Yards Directly
- You need 0.5 cubic yards.
- One 80 lb bag makes about 0.022 cubic yards.
Number of bags = Total Volume Needed (in yards) / Volume per Bag (in yards)
Number of bags = 0.5 cubic yards / 0.022 cubic yards per bag
Number of bags ≈ 22.7 bags
Again, round up to 23 bags.
Both methods give you about the same answer. Method 1 is often easier because the bag yield (0.6 cubic feet) is a rounder number than the cubic yard yield (0.022).
How a Concrete Bag Volume Calculator Helps
Figuring out these numbers can take time. It’s easy to make a math mistake. This is where a concrete bag volume calculator online can be helpful.
You usually put in the size of your area (length, width, thickness). The calculator does the math for you. It tells you the total cubic feet or cubic yards needed. Then it asks what size concrete bag you are using (like 80 lb). It will then tell you how many bags to buy.
These calculators use the standard yield numbers. Like 0.6 cubic feet for an 80 lb bag. They are a quick way to check your own math or get a fast estimate. Just search online for “concrete bag calculator”.
Other Common Bag Sizes and Their Yields
While the 80 lb bag is common, you might see other sizes. It’s good to know their yields too.
- 40 lb bag: Makes about 0.3 cubic feet. (Half of an 80 lb bag’s yield).
- 50 lb bag: Makes about 0.375 cubic feet. (A bit more than the 40 lb bag).
- 60 lb bag: Makes about 0.45 cubic feet. (More than half, less than the 80 lb).
These yields are also approximate. Check the bag label for the most accurate number.
Let’s put these yields in a table, along with the 80 lb bag, and show their volume in both cubic feet and cubic yards.
h4. Approximate Yields of Different Concrete Bag Sizes
| Bag Size | Approximate Yield (Cubic Feet) | Approximate Yield (Cubic Yards = Cu Ft / 27) |
|---|---|---|
| 40 lb | 0.3 cubic feet | 0.011 cubic yards |
| 50 lb | 0.375 cubic feet | 0.014 cubic yards |
| 60 lb | 0.45 cubic feet | 0.017 cubic yards |
| 80 lb | 0.6 cubic feet | 0.022 cubic yards |
This table is a quick guide. It helps you compare bag sizes. You can see that two 40 lb bags (0.3 + 0.3 = 0.6 cu ft) make about the same as one 80 lb bag (0.6 cu ft). Two 60 lb bags (0.45 + 0.45 = 0.9 cu ft) make more than one 80 lb bag.
Using this table, you can figure out the cubic yards from concrete bags no matter the bag size. You just find the cubic feet yield for that bag size and divide by 27.
Factors That Change the Real Yield
Remember that 0.6 cubic feet number for an 80 lb bag is an estimate. The actual amount you get can be slightly different.
Things that can change the yield:
* How much water you add: Using more water than the bag says can make the concrete flow easier, but it also can slightly increase the wet volume. However, it makes the concrete weaker and can lead to more shrinkage as it dries, which might affect the final hardened volume. Using the correct amount of water is best for strength and reaching the stated yield.
* Mixing: Making sure all the dry mix gets wet and mixed well is important. Dry clumps don’t add to the wet volume.
* Air content: Mixing can add tiny air bubbles. Professional concrete has specific air added, but hand-mixing bagged concrete can also trap some air. This can slightly affect the final volume.
* Wasted mix: Some concrete might stick to your tools or mixer. This means less concrete ends up in your form.
For most home projects, using the 0.6 cubic feet number is close enough. But if you are doing a very large project with many bags, these small differences can add up. It’s another reason why buying an extra bag or two is a good idea.
Planning for Waste and Extras
When you calculate concrete bags needed, you should always plan for a little bit extra.
Why?
* Your hole or form might be a bit bigger than you measured.
* You might spill some mix or wet concrete.
* The ground might soak up some water if you are pouring directly on soil.
* It’s better to have too much than too little. If you are short, you have to stop work and go buy more bags. The concrete you already poured might start to harden.
A common rule is to add 5% to 10% extra bags to your total number.
Example: You calculated you need 23 bags for that 0.5 cubic yard job.
Add 10% for safety: 23 bags * 0.10 = 2.3 bags.
Round up to 3 extra bags.
Total bags to buy: 23 + 3 = 26 bags.
This small extra cost is worth it to avoid problems during your project.
Breaking Down the Cubic Yard Calculation Again
Let’s just review the main cubic yard point one more time to make it extra clear.
You want to know how much of a cubic yard one 80 lb bag makes.
-
An 80 lb bag gives about 0.6 cubic feet of concrete when mixed. This is the concrete yield 80 lb bag. It’s also the 80 lb concrete yield cubic feet. It shows how much concrete does 80 lb bag make in terms of space. It’s the volume of concrete bag. It tells you how many cubic feet in 80 lb bag after mixing.
-
A cubic yard is a large box of space. It holds 27 cubic feet.
-
To see how many 0.6 cubic feet portions fit into a 27 cubic foot space, you divide the large space by the small portion size.
27 cubic feet (1 cubic yard) / 0.6 cubic feet (per bag) = 45 bags.This calculation tells you that it takes about 45 eighty-pound bags of concrete to make one cubic yard.
-
If it takes 45 bags to make 1 cubic yard, then one bag makes 1/45th of a cubic yard.
1 / 45 ≈ 0.022This confirms our earlier math. One 80 lb bag makes approximately 0.022 cubic yards. This is the amount of cubic yards from concrete bags (specifically one 80 lb bag).
Understanding this relationship helps you connect the small volume you get from a bag to the larger volumes often used in bigger construction talk.
Using Coverage for Simple Estimates
Sometimes, just knowing the coverage helps for quick estimates, especially for flat areas like paths or floors.
If you need a sidewalk 3 feet wide, 10 feet long, and 4 inches thick:
Total Area = Length x Width = 10 ft x 3 ft = 30 square feet.
We saw that one 80 lb bag covers about 1.8 square feet at 4 inches thick.
Number of bags = Total Area Needed / Coverage per Bag
Number of bags = 30 sq ft / 1.8 sq ft per bag
Number of bags ≈ 16.67 bags
Round up to 17 bags. Add a couple extra for safety, say 19 bags total.
This method uses the concrete coverage per bag number directly. It’s a shortcut for flat areas when you know the thickness you need. You can use the table provided earlier to find the coverage number for your needed thickness.
Keeping it Simple
The main thing to remember about an 80 lb bag of concrete is that it makes about 0.6 cubic feet.
From there, you can:
* Figure out the total cubic feet your project needs.
* Divide project cubic feet by 0.6 to get the number of 80 lb bags.
* If your project volume is in cubic yards, multiply it by 27 first to get cubic feet, then divide by 0.6. Or use the 0.022 cubic yards per bag number if you prefer.
* If you know the area and thickness, find the coverage per bag for that thickness (like 1.8 sq ft at 4 inches thick) and divide your total area by that number.
Always round up the number of bags and buy a little extra.
Using the numbers 0.6 cubic feet or 0.022 cubic yards (which are the same amount of concrete!) for an 80 lb bag will help you buy the right amount for your project. This saves you time, money, and stress. It also helps you use the concrete bag volume calculator correctly. Knowing the concrete yield 80 lb bag is a basic step for any concrete work. It’s all about figuring out how much concrete does 80 lb bag make in a way that makes sense for your project size. You are simply finding the cubic feet per 80 pound concrete bag and then changing it to other numbers you can use, like cubic yards or square feet of coverage.
Frequently Asked Questions (FAQ)
h5. How many cubic feet are in an 80 lb bag of concrete mix?
An 80 pound bag of standard concrete mix makes about 0.6 cubic feet of mixed concrete. This is the amount of space the wet concrete will fill.
h5. How much concrete does an 80 lb bag actually yield?
The concrete yield 80 lb bag is roughly 0.6 cubic feet. This means after you add water and mix it, you get about 0.6 cubic feet of usable concrete material.
h5. How many 80 lb bags make one cubic yard?
One cubic yard is equal to 27 cubic feet. Since an 80 lb bag makes about 0.6 cubic feet, you would need to divide 27 by 0.6 to find out how many bags make a yard. 27 / 0.6 = 45. So, it takes about 45 eighty-pound bags to make one cubic yard of concrete.
h5. What is the volume of an 80 lb concrete bag?
The dry mix in the bag has a certain volume, but the useful volume of concrete bag refers to the mixed, wet volume it creates. For an 80 lb bag, this is about 0.6 cubic feet.
h5. How do I calculate how many bags of concrete I need?
First, find the total volume of your project space in cubic feet (Length x Width x Thickness, using feet for all measurements). Then, divide your total cubic feet needed by the yield of one bag (0.6 cubic feet for an 80 lb bag). Round up to the next whole bag and add a few extra for safety. This is how you calculate concrete bags needed.
h5. How much area does an 80 lb bag cover?
The concrete coverage per bag depends on the thickness you are pouring. For example, at a 4-inch thickness (0.333 feet), one 80 lb bag covers about 1.8 square feet (0.6 cubic feet / 0.333 feet). Check the table above for other thicknesses.
h5. Can I use a concrete bag volume calculator?
Yes, using a concrete bag volume calculator online is a fast way to figure out how many bags you need. You usually put in your project size, the thickness, and the bag size you plan to use (like 80 lb).
h5. Is the yield number (0.6 cubic feet) always exact?
No, the yield is an estimate. It can change a little based on how much water you add, how well you mix, and the exact mix ingredients. But 0.6 cubic feet is a standard and reliable number for planning.
h5. What is the difference between cubic feet and cubic yards for concrete?
Cubic feet and cubic yards are both ways to measure volume (the amount of space something fills). A cubic foot is a smaller unit (like a 1ft x 1ft x 1ft box). A cubic yard is a much larger unit (like a 3ft x 3ft x 3ft box) and holds 27 cubic feet. Concrete bags are usually measured in cubic feet yield, while large concrete orders are in cubic yards. You need to know the conversion (1 yard = 27 feet) to go between them.