Essential Concrete Bags per Yard: 40, 60, 80
Direct Answer: How Many Bags Are in a Cubic Yard?
One cubic yard equals 27 cubic feet. So the number of bags you need depends on how much finished concrete each bag makes, which manufacturers call the yield.
Using the yields printed on widely sold standard concrete mixes, one cubic yard takes roughly:
- About 45 80-lb bags, when each bag yields 0.60 cubic feet
- About 60 60-lb bags, when each bag yields 0.45 cubic feet
- About 90 40-lb bags, when each bag yields 0.30 cubic feet
These are planning figures based on common listed yields, not a fixed industry rule. Before you buy, check the bag label or product data sheet for the exact mix you are using, because yields differ between products.
Estimate based on the example yields above
| Bag weight | Example finished yield per bag | Approximate bags for 1 cubic yard | With 10% extra |
|---|---|---|---|
| 40 lb | 0.30 ft³ | 90 | 99 |
| 60 lb | 0.45 ft³ | 60 | 66 |
| 80 lb | 0.60 ft³ | 45 | 50 |
This table is an estimate built from the example yields shown, which match the published figures for several mainstream standard concrete mixes. It is not a universal manufacturer rule, and specialty products can differ sharply. One high-yield product, for example, states that a single 80-lb bag makes roughly 1 cubic foot, which would change the count to about 27 bags per yard.
Concrete Bag Calculator
A good on-page concrete bag calculator removes the arithmetic and the guesswork. Here is the tool From Hippotool .
Inputs the calculator should accept:
- Shape: rectangular slab, circular slab, or cylindrical hole such as a post hole
- Length and width in feet and inches, or diameter for round shapes
- Depth or slab thickness in inches
- Bag weight selection: 40 lb, 60 lb, or 80 lb
- Custom bag yield in cubic feet, so users can enter the figure from their own label
- Waste allowance, with 5% and 10% presets
Outputs the calculator should return:
- Project volume in cubic feet
- Project volume in cubic yards
- Baseline bags required, before any allowance
- Total bags to buy after the waste allowance, rounded up to whole bags
The calculator should default to the common example yields of 0.30, 0.45, and 0.60 cubic feet, since those match several mainstream standard mixes. It must also let users overwrite that default with the yield printed on their own product label, because a fast-setting 50-lb mix lists about 0.375 cubic feet and a sand/topping mix lists a different figure again.
The formulas behind it are simple:
Bags required = project volume in cubic feet ÷ listed finished yield per bag
Bags to buy = round up [bags required × (1 + waste allowance)]
This is a material-estimate tool. It does not size slabs, reinforcement, or footings, and it is not a structural-design calculator.
Why a Cubic Yard Equals 27 Cubic Feet
Picture a cube that measures three feet on every side. Multiply the sides and you get the volume:
3 ft × 3 ft × 3 ft = 27 cubic feet
That cube is one cubic yard, which equals 27 cubic feet or 46,656 cubic inches. Ready-mix suppliers price and deliver concrete by the cubic yard, so this number is the bridge between your tape measure and a supplier’s quote.
Concrete is estimated by volume because you are filling a space of a certain size. Bags, though, are sold by dry weight, which is just the weight of the cement, sand, and stone inside before you add water. Weight tells you what you are lifting; only the yield tells you how much space the mixed concrete will fill.
40 lb vs. 60 lb vs. 80 lb Concrete Bags
| Bag size | Common project fit | Example yield | Approximate bags per cubic yard | Handling notes |
|---|---|---|---|---|
| 40 lb | Small repairs, single post holes, stepping stones, tight spaces | 0.30 ft³ | 90 | Lightest to carry, but you open the most bags |
| 60 lb | Sidewalks, small pads, several post holes, mid-size DIY work | 0.45 ft³ | 60 | A common balance of weight and bag count |
| 80 lb | Patios, larger slabs, driveway repairs | 0.60 ft³ | 45 | Fewest bags, heaviest lift, easiest to strain your back |
Verify the yield on your product before ordering. These figures come from published data for standard concrete mixes and do not automatically apply to every bag on the shelf.
How Many 80-lb Bags of Concrete Are in a Yard?
Divide the cubic yard by the bag’s yield:
27 ÷ 0.60 = 45
That gives approximately 45 80-lb bags for one cubic yard, before any extra material, based on a listed yield of 0.60 cubic feet per bag. Flip the math and one 80-lb bag holds about 0.60 ÷ 27 = 0.022 cubic yards.
How Many 60-lb Bags of Concrete Are in a Yard?
27 ÷ 0.45 = 60
So one cubic yard takes approximately 60 60-lb bags before extra material, based on a listed yield of 0.45 cubic feet per bag.
How Many 40-lb Bags of Concrete Are in a Yard?
27 ÷ 0.30 = 90
That works out to approximately 90 40-lb bags per cubic yard before extra material, using a listed yield of 0.30 cubic feet per bag. Ninety bags is a lot of mixing, which is why most people move up to larger bags or price ready-mix once a project grows.
How to Calculate Bags of Concrete From Dimensions
Step 1: Measure Length, Width, and Thickness
Measure the finished space you plan to fill, not the rough hole. Keep every dimension in the same unit, and convert thickness from inches to feet:
Thickness in feet = thickness in inches ÷ 12
A 4-inch concrete slab is 4 ÷ 12 = 0.333 feet thick. Check thickness in several places, since a subgrade that dips even half an inch adds real volume.
Step 2: Find Project Volume in Cubic Feet
Cubic feet = length (ft) × width (ft) × depth (ft)
Break irregular projects into simple rectangles and circles, calculate each one, then add the results together.
Step 3: Convert to Cubic Yards
Cubic yards = cubic feet ÷ 27
You need this figure to compare bag pricing against a ready-mix quote, because suppliers sell by the yard.
Step 4: Divide by the Bag’s Listed Yield
Bags required = project cubic feet ÷ bag yield in cubic feet
Use the yield printed on your bag or its technical data sheet. Manufacturer instructions follow this same method: work out cubic feet, then divide by the yield for your bag size.
Step 5: Add Waste and Round Up
Add a 5% to 10% material allowance, then round up to whole bags. You cannot buy 55.6 bags, and a partial bag mixed at the wrong ratio is not usable concrete. Running short mid-pour is the worse outcome, because fresh concrete stiffens while you drive to the store, and a delayed fill creates a cold joint where the two pours never bond properly.
Real-World Concrete Bag Examples
Every example below assumes a standard concrete mix with the listed yield noted in the calculation.
Example 1: 10 ft × 10 ft Patio Slab at 4 Inches Thick
- Thickness in feet: 4 ÷ 12 = 0.333 ft
- Volume: 10 × 10 × (4 ÷ 12) = 33.33 cubic feet
- Cubic yards: 33.33 ÷ 27 = 1.23 cubic yards
- Bags required at 0.60 ft³ per 80-lb bag: 33.33 ÷ 0.60 = 55.56, so 56 bags before extra material
- With 10% extra: 55.56 × 1.10 = 61.12, so 62 bags
This result assumes a bag yield of 0.60 cubic feet, which matches the published figure for standard 80-lb concrete mix. Independent estimating tools reach the same ballpark for this slab, at roughly 1.23 cubic yards and about 56 80-lb bags.
Example 2: 4 ft × 20 ft Sidewalk at 4 Inches Thick
- Volume: 4 × 20 × (4 ÷ 12) = 26.67 cubic feet
- Cubic yards: 26.67 ÷ 27 = 0.99 cubic yards
- Bags required at 0.45 ft³ per 60-lb bag: 26.67 ÷ 0.45 = 59.26, so 60 bags before extra material
- With 10% extra: 59.26 × 1.10 = 65.19, so 66 bags
This assumes a listed yield of 0.45 cubic feet per 60-lb bag. A walkway this size sits right at one cubic yard, which is exactly the point where it pays to phone a local supplier and compare a small ready-mix load against 66 bags.
Example 3: Fence-Post Hole
For a round hole, use the cylinder volume formula, where r is the radius and h is the depth:
Volume = πr²h
Take a hole 10 inches across and 36 inches deep:
- Radius: 10 ÷ 2 = 5 inches, or 5 ÷ 12 = 0.417 ft
- Depth: 36 ÷ 12 = 3 ft
- Volume: 3.1416 × 0.417² × 3 = 1.64 cubic feet
- Bags at 0.60 ft³: 1.64 ÷ 0.60 = 2.73, so 3 bags per hole
The post itself takes up space inside the hole, so the real concrete needed is lower. A 4×4 post, which measures about 3.5 inches square, occupies roughly 0.26 cubic feet over that 3-foot depth, trimming the fill to about 1.38 cubic feet, or 2.3 bags. Many people ignore this and let the post volume act as a built-in cushion.
This is a material estimate only. Post-hole depth, diameter, and footing design for load-bearing or braced structures should follow local building codes, and manufacturer guidance says the same.
Useful Coverage Reference Chart
All rows below assume a bag yield of 0.60 cubic feet per 80-lb bag, matching published data for standard 80-lb concrete mix.
| Slab size and thickness | Cubic feet | Cubic yards | 80-lb bags before waste | Bags with 10% extra |
|---|---|---|---|---|
| 6 ft × 6 ft at 4 in | 12.00 | 0.44 | 20 | 22 |
| 8 ft × 8 ft at 4 in | 21.33 | 0.79 | 36 | 40 |
| 10 ft × 10 ft at 4 in | 33.33 | 1.23 | 56 | 62 |
| 10 ft × 12 ft at 4 in | 40.00 | 1.48 | 67 | 74 |
| 10 ft × 10 ft at 6 in | 50.00 | 1.85 | 84 | 92 |
These are estimates. Enter your actual bag yield into the calculator above, since a different mix changes every number in this chart.
Bagged Concrete vs. Ready-Mix Concrete
| Factor | Bagged concrete | Ready-mix delivery |
|---|---|---|
| Best use cases | Post holes, repairs, small pads, staged work you can pour over days | Larger slabs, driveways, single continuous pours |
| Labor and time | You haul, mix, and place every bag; slow with few helpers | Arrives mixed; the clock starts the moment the truck does |
| Access and logistics | Bags fit through gates, up stairs, and into backyards | Needs truck access or a pump; chute reach is limited |
| Cost variables | Local bag price, number of bags, mixer rental, your own time | Price per cubic yard, delivery, possible short-load and waiting charges |
| Waste and cleanup | Buy in stages, keep unopened bags dry; you clean the mixer | Leftover concrete in the truck is still charged; less tool cleanup |
Bagged concrete tends to win on convenience for small or awkward-access work, since you mix only what you can place at once. Ready-mix is worth pricing when the volume climbs or when the pour must happen in one continuous placement, because hand-mixing dozens of bags stretches the timeline and risks cold joints.
There is no universal yardage where ready-mix becomes the cheaper choice. Ready-mix material pricing and short-load charges vary by market, and published cost ranges are only rough guides. Ask your local supplier three questions before deciding: the price per cubic yard, the minimum load, and any short-load or waiting fees that apply to your order.
Factors That Change How Many Bags You Need
- The product’s listed finished yield, which is the single biggest variable
- Mix type and formulation, since standard, fast-setting, high-strength, crack-resistant, and topping mixes list different yields
- Final slab thickness, where an extra half inch on a 10×10 pad adds over 4 cubic feet
- Uneven excavation or a soft subgrade that swallows extra concrete
- Form movement, bulging, or overfill at the edges
- Spillage, plus the residue left clinging inside a mixer or wheelbarrow
- Posts, rebar, mesh, sleeves, or other embedded items that displace concrete
- The waste allowance you choose, typically 5% to 10% for residential work
- Product and unit differences between countries, including metric bag sizes
Common Mistakes to Avoid
- Treating bag weight as finished concrete volume. An 80-lb bag is 80 pounds of dry material, and its yield is a separate published number.
- Forgetting to convert inches to feet. Using 4 instead of 0.333 overstates a slab twelvefold.
- Buying exactly the mathematical minimum with no allowance for spillage or a low spot.
- Rounding bag counts down. Always round up to the next whole bag.
- Assuming every 60-lb or 80-lb product yields the same volume. Some specialty mixes state very different figures.
- Confusing concrete mix with cement, mortar, grout, or sand mix. Mortar is designed to bond masonry units, not to be poured as structural concrete, and sand/topping mix is meant for thin overlays rather than full-depth slabs.
- Using a material estimator as structural engineering guidance.
- Ignoring safe lifting, mixing instructions, and label safety warnings. Manufacturers direct users to wear impervious gloves, eye protection, and a mask, because wet mix can cause severe skin burns and dust exposure carries lung risks.
For Readers Outside the US
US projects are usually planned in cubic yards, feet, inches, and pound-based bag sizes such as 40, 60, and 80 lb. In Canada, the UK, Australia, and New Zealand, you are more likely to see cubic meters, millimeters, kilograms, and metric bag sizes; the same brands sell 25 kg and 30 kg bags in Canada, with yields published in cubic meters.
For conversions, one cubic yard is approximately 0.7646 cubic meters. UK ready-mix is quoted per cubic metre, and suppliers there apply their own minimum-load and partial-load policies.
The method does not change. Work out the finished volume you need, divide by the manufacturer’s stated bag yield in the same unit system, add a reasonable allowance, and round up to whole bags.
Frequently Asked Questions
How many 60-lb bags of concrete make one cubic yard?
About 60 bags, from 27 ÷ 0.45, when the product lists a yield of 0.45 cubic feet per 60-lb bag. Confirm the yield on your own bag first.
How many 80-lb bags of concrete make one cubic yard?
About 45 bags, from 27 ÷ 0.60, based on a listed yield of 0.60 cubic feet per 80-lb bag. High-yield specialty mixes can need far fewer.
How many 40-lb bags of concrete make one cubic yard?
About 90 bags, from 27 ÷ 0.30, using a listed yield of 0.30 cubic feet per 40-lb bag.
How much concrete does a 60-lb bag make?
Standard 60-lb concrete mixes commonly list roughly 0.45 cubic feet of mixed concrete per bag. That equals about 0.017 cubic yards.
How much does an 80-lb bag of concrete cover?
At a 0.60 cubic foot yield, one 80-lb bag covers about 1.8 square feet at 4 inches thick, or roughly 3.6 square feet at 2 inches thick. Coverage falls as thickness increases.
How many bags of concrete do I need for a 10×10 slab?
A 10 ft × 10 ft slab at 4 inches is 33.33 cubic feet, or 1.23 cubic yards. That is about 56 80-lb bags at a 0.60 cubic foot yield, or 62 bags with a 10% allowance.
Should I buy extra bags of concrete?
Yes, a 5% to 10% allowance is sensible for most DIY jobs. Use closer to 5% for a simple, carefully formed slab on a compacted base, and 10% for first-time work, uneven excavation, irregular holes, or when you are unsure of your measurements. An allowance is a cushion, not a replacement for accurate measuring and good site prep.
Is it cheaper to buy bags of concrete or order ready-mix?
It depends on your local bag price, the ready-mix price per yard, delivery and short-load fees, site access, project volume, and how many people you have to mix and place. There is no fixed volume at which one is always cheaper, so get a local quote and compare it against your bag count.
How many bags of concrete come on a pallet?
Pallet quantities vary by product, bag size, manufacturer, and retailer. One manufacturer lists 56 bags per pallet for a 60-lb mix and 42 per pallet for an 80-lb mix of the same product line, while a fast-setting 50-lb product is listed at 56 per pallet. Check the product page or ask your supplier for the pallet count you will actually receive.
How much water do I add to a 60-lb bag of concrete?
Follow the label, because water requirements differ by product. One standard mix lists a starting water content of 4 pints for a 60-lb bag with a maximum of about 7 pints, while another 60-lb product calls for roughly 2.5 to 3 quarts. Add water gradually to reach a workable, moldable consistency, and avoid overwatering, since excess water weakens the finished concrete.
Can I use this calculator for footings or foundations?
Use it to estimate material quantity only. Structural slabs, foundations, footings, retaining structures, and load-bearing work should follow local building codes and professional or engineering guidance, and manufacturers direct readers to local codes for load-bearing footing specifications.
Final Takeaway
Calculate your project volume in cubic feet, divide by the finished yield printed on the exact bag you are buying, then add 5% to 10% and round up to whole bags. That sequence is reliable at any project size, in any unit system, because it uses your real dimensions and your real product’s yield instead of a generic bag count.