Cubic Yards to Bags of Concrete

How much concrete one bag makes

One 80 lb bag of concrete mix makes about 0.60 cubic feet of concrete. That means you need 45 bags of 80 lb mix for one cubic yard, so each bag fills only about 1/45 of a yard. With 60 lb bags, it takes 60 bags to make a cubic yard.

The weight on the bag is the weight of the dry mix, not the amount of concrete you’ll end up with. What you’re really buying is the yield, which is the volume in cubic feet printed on the bag. The yields below come from the Quikrete Concrete Mix data sheet.

The total weight is the same no matter which bag size you buy. One cubic yard is about 3,600 lb of dry mix, whether that’s 45 bags of 80 lb or 60 bags of 60 lb. Keep that number in mind when you plan how many trips your pickup or cart can handle. Specialty mixes, such as fast-setting, crack-resistant, high-strength or lightweight, can yield a different amount. Always check the yield printed on your bag, and pick the matching size in the converter above.

A bag of cement is not a bag of concrete

Portland cement is only the binder, so a bag of it won’t make concrete by itself. Ready-mix recipes are described by how many bags, or “sacks,” of cement go into each cubic yard along with sand and gravel. Most recipes use five to six 94 lb bags of portland cement per cubic yard, according to the Quikrete Portland Cement data sheet.

If you mix your own from scratch, a common recipe by volume is 1 part cement, 2 parts sand and 3 parts gravel. So “bags of cement in a yard” and “bags of concrete in a yard” are two different numbers. This page counts bags of premixed concrete, which already contain the cement, sand and gravel.

Bags or ready-mix: where the line usually falls

Bags are the right choice for small jobs you can count in bags rather than yards. Once you reach about a full cubic yard, ready-mix is usually easier and is often cheaper. Ready-mix is concrete mixed at a plant and delivered by truck. Get a price for both before you decide, though, because small truck loads can come with extra fees.

One cubic yard of bagged concrete is a lot of physical work. It’s 45 bags of 80 lb mix, so you’ll lift, load and unload about 3,600 lb before you mix anything. Then you have to mix it batch by batch: plan on at least 1 cubic foot of mixer capacity for every 80 lb bag you mix at once.

The Cemex ready-mix FAQ points out that a full yard is far more than most DIY maintenance jobs need. Here’s how jobs usually split:

• Bags: minor repairs and small ramps
• Bags: fence posts and small patios
• Ready-mix: large patios and pool decks
• Ready-mix: driveways, foundation slabs and new sidewalks

Ready-mix plants usually have a minimum order. One large supplier sets its minimum at 1 cubic yard per delivery, and many plants charge extra for small loads, so check with your local plant. Truck sizes and short-load fees are covered on the concrete calculator page.

To compare the two options fairly, enter your store’s bag price in the converter above to get the total for bags. Then ask a local plant for a delivered price on the same number of cubic yards, including any small-load fee. Whichever way you buy, add about 10–15% extra for spillage and uneven ground. Running out halfway through a pour costs more than having a few bags left over.

Common small jobs, worked out

A 4 × 8 ft slab 4 inches thick takes 18 bags of 80 lb concrete mix, or 20 bags with 10% extra. A 10 × 10 ft slab at the same thickness takes 56 bags, or 62 with extra. For a sense of scale, one cubic yard poured 4 inches thick covers about 81 square feet, which is roughly a 9 × 9 ft slab. One 80 lb bag covers about 1.8 square feet at 4 inches.

For a fence post, dig the hole about three times as wide as the post. Make it about one-third of the post’s total length deep. For other shapes and sizes, get the cubic yards from the concrete calculator first, then enter that number in the converter above.

Cubic yards to bags of concrete FAQs