Convert between concrete bags and cubic yards. Supports 40, 50, 60, and 80 lb bags from all major brands.
The number of bags you need per cubic yard depends entirely on the bag size. An 80 lb bag yields approximately 0.60 cubic feet of mixed concrete, which means you need 45 bags to make one cubic yard (27 cubic feet divided by 0.60). A 60 lb bag yields about 0.45 cubic feet, requiring 60 bags per cubic yard. A 50 lb bag yields approximately 0.375 cubic feet, so you need 72 bags per cubic yard. And a 40 lb bag yields roughly 0.30 cubic feet, meaning you need 90 bags per cubic yard. The 80 lb bag is the most economical choice on a per-yard basis and is what most contractors reach for. The lighter bags cost more per cubic foot of concrete but are easier to handle, which matters when you are working alone or have physical limitations.
Quick Reference: Bags Per Cubic Yard
80 lb
0.60 cu ft/bag
45 bags/yd
60 lb
0.45 cu ft/bag
60 bags/yd
50 lb
0.375 cu ft/bag
72 bags/yd
40 lb
0.30 cu ft/bag
90 bags/yd
One of the most important decisions for any concrete project is whether to buy bags or order a ready-mix truck. The math is straightforward: at roughly $6 per 80 lb bag, you are paying about $270 per cubic yard for bagged concrete. A ready-mix truck delivers concrete at approximately $150 per cubic yard, nearly half the cost. The crossover point where a truck becomes the better deal is around 1 cubic yard. However, ready-mix trucks typically have minimum order requirements of 1 to 3 yards, and many charge short-load fees of $30 to $50 per yard below the minimum. A truck also requires that your site is accessible, your forms are ready, and you have enough people on hand to place the concrete before it starts setting. For projects under half a cubic yard, bags are almost always the practical choice. Between half a yard and one yard, it depends on your situation. Above one yard, call for a truck unless access is a problem.
Homeowners and contractors often ask whether there is a meaningful difference between Quikrete and Sakrete, the two dominant brands of bagged concrete in the United States. The short answer is that both brands meet ASTM C 387, the standard specification for packaged, dry, combined materials for concrete, and they are functionally identical in performance. Both produce concrete rated at 4,000 PSI at 28 days when mixed according to directions. In many regions, Quikrete and Sakrete are actually manufactured in the same plants using the same raw materials, with only the bag branding differing. Choose whichever brand is available at your local supplier and priced competitively. The brand on the bag matters far less than proper mixing technique, correct water ratio, and adequate curing time.
Bagged concrete comes in several formulations designed for specific applications. Standard concrete mix (4,000 PSI) is the workhorse product for most residential projects including slabs, footings, sidewalks, and patios. It is the least expensive option and provides plenty of strength for general use. Fast-setting concrete reaches initial set in 20 to 40 minutes, making it ideal for setting fence posts, mailbox posts, and sign posts where you do not want to build braces. You can pour it dry into the hole and add water on top for post-setting applications. High-strength concrete (5,000 PSI) is formulated for applications that need extra load-bearing capacity such as structural footings, equipment pads, and steps. Crack-resistant concrete contains synthetic fibers blended into the dry mix that help control plastic shrinkage cracking during curing. It is a good choice for slabs and flatwork where surface appearance matters. Each type is available in the standard bag sizes and the yield per bag remains the same regardless of the product formulation.
Before you load up your truck with bags of concrete, do the weight math. A cubic yard of concrete requires 45 bags of 80 lb mix, which totals 3,600 pounds of dry material. A standard half-ton pickup truck should not carry more than about 1,000 pounds in the bed, meaning you need multiple trips or a larger vehicle for anything over 12 bags. A three-quarter-ton truck can handle roughly 25 to 30 bags per trip. Plan your trips and your schedule accordingly, because bagged concrete has a shelf life of 6 to 12 months when stored in a dry location. Keep bags off the ground on pallets or plastic sheeting and under cover. Once moisture gets into a bag, the cement starts to hydrate and the bag will develop hard lumps that compromise the final concrete strength. In humid climates, buy only what you can use within a few months rather than stockpiling.
Getting the water ratio right is the single most important factor in achieving strong concrete from bagged mix. For an 80 lb bag, start with approximately 6 pints (3 quarts) of water and mix thoroughly before adding more. The maximum water content is about 9 pints, but using more water than necessary significantly reduces the final strength and increases cracking. Add water gradually and mix until the consistency resembles thick oatmeal. The concrete should hold its shape when squeezed in your hand but be wet enough to flow into forms and around reinforcement. Use a mixing tub, wheelbarrow, or portable mixer depending on the volume. For more than about 10 bags, a portable electric or gas mixer will save considerable time and effort and produce a more consistent mix than hand mixing. Always measure your water rather than guessing, and resist the temptation to add extra water to make the mix more workable.
Example: 4 ft x 4 ft x 4 in slab using 80 lb bags
Volume: 4 x 4 x (4/12) = 5.33 cubic feet
Bags needed: 5.33 / 0.60 = 8.89, round up to 9 bags
With 10% waste: 9 x 1.10 = 10 bags of 80 lb concrete
Total weight: 10 x 80 = 800 lbs
You need approximately 45 bags of 80 lb concrete to make one cubic yard. Each 80 lb bag yields about 0.60 cubic feet of mixed concrete, and there are 27 cubic feet in a cubic yard. Always buy a few extra bags to account for waste, spillage, and uneven subgrade conditions.
Bagged concrete costs approximately $270 per cubic yard when using 80 lb bags at around $6 each. Ready-mix from a truck runs about $150 per cubic yard. The crossover point is around 1 cubic yard, but trucks typically have minimum order requirements of 1 to 3 yards and may charge short-load fees for small orders. For projects under 1 cubic yard, bags are usually the practical choice.
Bagged concrete has a shelf life of 6 to 12 months when stored in a dry location off the ground. Keep bags on a pallet or plastic sheeting and protected from moisture. Once a bag absorbs moisture, the cement begins to hydrate and develops hard lumps. Hardened or lumpy bags should be discarded because the concrete will not reach its rated strength.
For an 80 lb bag, start with approximately 6 pints (3 quarts) of water and mix thoroughly. The maximum water content is about 9 pints, but using more water than necessary weakens the concrete and increases cracking. Add water gradually until the mix reaches a thick, oatmeal-like consistency that holds its shape when squeezed but flows into forms.
Fast-setting concrete sets in 20 to 40 minutes and reaches walkable strength in about 2 hours, making it ideal for setting fence posts, mailbox posts, and sign posts without bracing. Standard concrete takes 24 to 48 hours to set and reaches full strength in 28 days. Use standard mix for slabs, footings, and larger pours where you need more working time to place and finish the surface.