How Many Bags of Concrete Are in a Yard?

Bags per cubic yard by bag size

A bag of concrete mix is sold by weight, but a project is measured by volume. The link between them is the yield: how many cubic feet of finished concrete one bag makes when mixed with the right amount of water. Manufacturers print the yield on the bag or on the data sheet. QUIKRETE lists 0.60 ft³ for an 80 lb bag of Concrete Mix, 0.45 ft³ for 60 lb, 0.375 ft³ for 50 lb and 0.30 ft³ for 40 lb.

Divide 27 ft³ per yard by the yield and round up. That gives the table below.

The yield differs a little between brands and between mixes, such as high-strength or fast-setting products. Always read the number on the bag you are buying. The calculators on this site let you edit it.

How to work out the bag count for your project

1. Calculate the volume in cubic feet with the bag calculator or by hand.
2. Add waste, usually 10%.
3. Divide by the bag yield in cubic feet.
4. Round up to a whole bag.
5. Add a few spare bags for the unexpected low spot.

Worked example: a 10 × 10 ft slab, 4 in thick

1. Convert to feet (inches ÷ 12, centimeters ÷ 30.48): Length 10 ft; Width 10 ft; Thickness 4 in = 0.3333 ft
2. Volume = 10 × 10 × 0.3333 × 1 = 33.3333 ft³
3. Net volume = 33.3333 ft³ ÷ 27 = 1.2346 yd³ (× 0.0283168 = 0.9439 m³)
4. Order quantity = 1.2346 yd³ × (1 + 10%) = 1.358 yd³ = 36.6667 ft³
5. 80 lb bags = 36.6667 ft³ ÷ 0.6 ft³ per bag = 61.11 → 62 bags (always round up)
6. Weight = 36.6667 ft³ × 150 lb/ft³ = 5,500 lb

That slab needs 62 bags of 80 lb mix or 82 bags of 60 lb mix, including 10% waste. The weight of the dry mix alone is 4,960 lb for the 80 lb bags, about 2.48 tons, which matters when you think about hauling.

Which bag size is best?

The 80 lb bag gives the most concrete per trip and the lowest price per cubic foot in most stores, so it is the default for slabs and footings. It is also heavy: 80 lb is a lot to lift repeatedly. The 60 lb and 50 lb bags are easier to handle and suit post holes, repairs and jobs that you mix a bag at a time. The 40 lb bag is mainly for tiny repairs. If you are mixing in a wheelbarrow, a 60 lb bag may be the practical limit for a single person.

Pallets and delivery

Stores sell bags on pallets. A pallet of 80 lb bags usually holds 42 bags, a pallet of 60 lb bags 56 and a pallet of 50 lb bags 64. A pallet of 80 lb mix is 3,360 lb of product, so you need a forklift or a pallet jack, and a truck rated for the load. The pallet calculator converts a bag count into pallets and loose bags.

Why the exact count is never exact

• Yield changes with how much water you add. Too much water gives a larger volume but a weaker mix.
• Different products have different yields. A high-strength mix may yield slightly differently from a standard mix.
• Forms and base are never perfectly level, so the real volume differs from the drawing.
• Mixing loses some material to spills and to the barrow.

When bags stop making sense

Mixing 45 bags for a single yard takes a mixer and several people. By two yards you are handling 90 bags and moving 7,200 lb of dry mix. Most guides advise ready-mix beyond about 2 yd³. Compare the prices with the cost calculator, and read bagged vs ready-mix concrete before you decide.

Bag counts for common 4 in slabs

The bag counts shown include 10% waste and are rounded up. They rise fast with size, which is why anything larger than a small patio is normally ordered by the yard from a plant. See the full fractional yards to bags chart for smaller volumes.

Reading the label before you buy

Check three things on the bag: the weight, the yield in cubic feet and the amount of water. A “80 lb” bag of a high-strength or fast-setting mix may have a different yield from the standard mix. Mixes with larger stone are cheaper per bag but are not suitable for thin sections. Sand (topping) mix and mortar mix contain no coarse stone and are for thin repairs and masonry; do not use them for slabs or footings.

Types of bagged mix

• Concrete mix: the general-purpose product for slabs, footings and steps.
• Fast-setting mix: sets in minutes, suited to post holes. Mix small amounts.
• High-strength mix: for loads and thin sections where more strength is needed.
• Crack-resistant mix: includes fibers that reduce shrinkage cracking.
• Sand mix: no coarse stone, for toppings and thin repairs.
• Mortar mix: for brick and block laying only.

Example: planning a small shed pad

A shed pad of 8 × 8 ft and 4 in thick needs 0.79 yd³ net. With 10% waste the order is 0.87 yd³, which is 40 bags of 80 lb mix, or 53 bags of 60 lb mix. If you can mix two bags at a time in a wheelbarrow, that is about 20 batches. Plan the pour for a mild day, mix the batches near the pad, and keep a helper on the screed. If you cannot finish the pour within a few hours, a truck delivery is the safer choice.

The same steps apply for any job: find the volume, add waste, divide by the bag yield and round up. Buy a few bags more than the number you calculated and return the unopened extras if the store allows it.

Frequently asked questions