Cubic Feet of Concrete per Bag: How Many in 40/60/80 lb?

How many cubic feet are in a bag of concrete? Most standard concrete mix bags use these planning yields: a 40 lb bag makes about 0.30 cubic feet, a 60 lb bag makes about 0.45 cubic feet, and an 80 lb bag makes about 0.60 cubic feet of mixed concrete.

If you searched for "cubic ft of concrete per bag", the quick answer is: standard bagged concrete is commonly estimated at 0.30 ft3 for a 40 lb bag, 0.45 ft3 for a 60 lb bag, and 0.60 ft3 for an 80 lb bag. Product labels can vary, so use the printed yield for final buying.

Direct answer:

For final buying, add waste before rounding up. With 10% waste, one cubic yard is about 99 40 lb bags, 80 50 lb bags, 66 60 lb bags, or 50 80 lb bags.

Use the Concrete Bag Calculator when you want to turn project dimensions, waste factor, and bag price into a whole-bag buying estimate. This page is the quick cubic-foot yield chart to check before you calculate. For the focused 60 lb answer, see how much concrete a 60 lb bag makes. For the focused 80 lb answer, see 80 lb bag of concrete cubic feet and yield. For the focused 40 lb answer, see how much concrete a 40 lb bag makes.

If you are asking how many square feet one bag covers at a slab thickness, use the concrete bag coverage chart by slab thickness. If you are converting a full cubic yard into bags, see the Concrete Bags per Yard Guide. If the issue is a mismatch between calculated volume, bags purchased, and ready-mix delivery tickets, use the Concrete Yield Calculator Guide to compare planned yield with field and quote records.

Quick answer

Common planning yields for standard bagged concrete:

Always check the yield printed on the exact product you plan to buy. Specialty mixes, high-strength mixes, fast-setting mixes, and local store brands may use different yields.

Citation-ready concrete bag yield chart

Use this compact chart when you need to cite bag yield quickly in a DIY guide, resource list, or estimating checklist.

Suggested citation:

<a href="https://concreteestimatorhub.com/blog/cubic-feet-of-concrete-per-bag">cubic feet of concrete per bag chart</a>

For publisher notes and citation examples, see Link to Concrete Calculator Hub.

Fast bag-yield shortcuts

Why bag weight is not the same as cubic feet

Concrete bags are sold by dry weight, but project volume is measured in cubic feet or cubic yards. The bag weight tells you how heavy the dry mix is. The yield tells you how much mixed concrete volume the bag should produce.

That is why a bag-count estimate should use the printed yield, not just the bag weight. For normal planning, these shortcuts are useful:

If the bag does not list a yield, use the calculator result only as a rough planning estimate and confirm the product data before buying a large quantity.

Convert cubic feet of concrete into bags

If you already know the project volume in cubic feet, divide by the bag yield, then round up after waste:

bags to buy = round up(cubic feet needed / cubic feet per bag x 1.10)

For a 10% waste factor, these quick counts are useful:

These are buying counts, not exact mathematical counts. They include 10% waste and are rounded up to whole bags.

Formula for cubic feet per bag

Start with project volume in cubic feet:

cubic feet = length ft x width ft x thickness ft

If thickness is measured in inches:

cubic feet = length ft x width ft x thickness in / 12

Then divide by the yield of one bag:

bags needed = project cubic feet / cubic feet per bag

Add waste before rounding up:

bags to buy = round up(bags needed x (1 + waste percentage))

For simple forms, 5% to 10% waste is common. Uneven bases, thick edges, spills, and irregular shapes may need more.

Example: 10 cubic feet of concrete

Assume you need 10 cubic feet of concrete before waste.

The total dry weight is still significant. Nineteen 80 lb bags is about 1,520 lb of dry material before water, tools, pallets, or transport.

Example: 1 cubic yard of concrete

One cubic yard equals 27 cubic feet.

40 lb bags: 27 / 0.30 = 90 bags
60 lb bags: 27 / 0.45 = 60 bags
80 lb bags: 27 / 0.60 = 45 bags

With 10% waste, that becomes about 99 bags of 40 lb concrete, 66 bags of 60 lb concrete, or 50 bags of 80 lb concrete.

At one cubic yard, compare the bagged plan with Ready-Mix vs Bags Cost before buying. The math may be correct, but moving and mixing dozens of bags can be the hard part.

Convert bag yield into slab coverage

Coverage is cubic-foot yield divided by slab thickness in feet:

coverage square feet = bag yield cubic feet / thickness feet

At 4 inches thick:

For the full 2, 3, 4, 5, and 6 inch coverage table, use the 40, 60, and 80 lb concrete bag coverage chart.

Cubic feet, coverage, and bags per yard compared

Use cubic feet when the project is measured by volume, coverage when the project is measured by square feet and thickness, and bags per yard when you are comparing bagged concrete with ready-mix.

This matters because the same bag can be described three ways. An 80 lb bag commonly yields about 0.60 ft3, covers about 1.8 sq ft at 4 inches thick, and takes about 45 bags to make one cubic yard before waste.

How this compares with broad concrete calculators

Manufacturer calculators are useful when you already know a product family and slab thickness. The QUIKRETE concrete calculator shows 40, 50, 60, and 80 lb bag outputs for 4 inch and 6 inch slab entries and notes that yields are approximate. Broad calculators such as the Inch Calculator concrete calculator also include pre-mixed bag outputs and a bag-per-yard table, but their main workflow starts with total concrete volume.

This page fills the narrower search intent: when the question is simply how many cubic feet are in one concrete bag, answer the bag-yield question first, then send the reader to the full bag calculator, coverage chart, or ready-mix comparison only if they need the next step.

Cost per cubic foot

When two bag sizes are close in shelf price, compare cost per cubic foot:

cost per cubic foot = bag price / bag yield cubic feet

Example:

80 lb bag at $6.50: 6.50 / 0.60 = $10.83 per ft3
60 lb bag at $5.25: 5.25 / 0.45 = $11.67 per ft3
40 lb bag at $4.25: 4.25 / 0.30 = $14.17 per ft3

The cheapest bag on the shelf is not always the cheapest concrete by volume. Also compare lifting weight, vehicle payload, delivery, mixer capacity, and whether extra unopened bags can be returned.

When the printed yield matters most

Use the exact product yield instead of a shortcut when:

• You are buying more than a few bags.
• The product is fast-setting, high-strength, crack-resistant, or lightweight.
• A store substitutes a different brand or bag size.
• The project has a tight budget or a hard delivery window.
• Running short would leave a cold joint or unfinished edge.

For a small repair, a common yield shortcut is often enough for planning. For a slab, footing, or large bag order, confirm the product first and then calculate.

Related bag guides

• 40 lb Concrete Bag Calculator
• 60 lb Concrete Bag Calculator
• 80 lb bag of concrete cubic feet and yield
• Concrete Bag Coverage Chart
• Concrete Bags per Yard Guide
• How Many 40 lb Bags of Concrete Are in a Yard?
• How Many 60 lb Bags of Concrete Are in a Yard?
• How Many 80 lb Bags of Concrete Are in a Yard?
• How Much Is a Bag of Concrete?
• How Many Bags of Concrete Are on a Pallet?

FAQ

How many cubic feet are in an 80 lb bag of concrete?

An 80 lb bag of standard concrete mix commonly yields about 0.60 cubic feet of mixed concrete. Always check the product bag for the exact yield.

What is the volume of an 80 lb bag of concrete?

For estimating, the volume of an 80 lb concrete bag is its mixed yield. A common planning value is about 0.60 ft3, or about 0.022 yd3, per 80 lb bag.

How many cubic feet are in a 60 lb bag of concrete?

A 60 lb bag commonly yields about 0.45 cubic feet of mixed concrete. With that yield, one cubic yard takes about 60 bags before waste.

How many cubic feet are in a 40 lb bag of concrete?

A 40 lb bag commonly yields about 0.30 cubic feet of mixed concrete. With that yield, one cubic yard takes about 90 bags before waste.

How many 80 lb bags make one cubic yard?

One cubic yard is 27 cubic feet. At 0.60 cubic feet per 80 lb bag, one cubic yard takes about 45 bags before waste or about 50 bags with 10% waste.

How many cubic feet are in a concrete bag?

It depends on the bag size and product. Common planning yields are about 0.30 ft3 for a 40 lb bag, 0.45 ft3 for a 60 lb bag, and 0.60 ft3 for an 80 lb bag.

Is bag yield the same as coverage?

No. Yield is cubic feet of mixed concrete per bag. Coverage is the square feet one bag covers at a specific slab thickness.

Can I estimate cubic feet from bag weight alone?

Only roughly. Bag weight is not the same as mixed volume. Use the printed yield on the bag or a common planning yield for the bag size, then add waste and round up.

Next step

Open the Concrete Bag Calculator to calculate your exact bag count, waste, and material cost. If the result is close to a pallet or a cubic yard, compare the plan with Ready-Mix vs Bags Cost before buying.