Updated June 17, 2026
It takes about 45 80-lb bags or 60 60-lb bags to make one cubic yard of concrete, because each 80-lb bag yields roughly 0.60 cubic feet and there are 27 cubic feet in a yard.
Bags per cubic yard: full reference table
| Bag size | Yield (cu ft) | Bags per cu yd | Typical cost per bag | Cost per yard (bags only) |
|---|---|---|---|---|
| 40 lb | 0.30 | 90 | ~$5 | ~$450 |
| 60 lb | 0.45 | 60 | ~$7 | ~$420 |
| 80 lb | 0.60 | 45 | ~$9 | ~$405 |
Ready-mix concrete delivered typically runs $150 to $200 per cubic yard depending on your region. For jobs over 1 cubic yard, ready-mix is almost always cheaper per yard when you factor in labor and mixer rental. Use the Concrete Calculator to compare costs for your project size.
How many 80-lb bags for a 12 x 12 slab?
A 12 x 12 ft slab at 4 inches thick is about 1.78 cubic yards. At 45 bags per yard that is roughly 80 to 85 bags of 80-lb concrete. At 6 inches thick it jumps to about 2.67 yards, or 120 bags. That is a lot of hand mixing; most contractors would call for ready-mix at that size.
Is it cheaper to mix your own or buy bags?
For very small jobs (under about 0.5 yards), bags are usually cheaper and more convenient because ready-mix trucks have a minimum charge and short-load fees. For anything over 1 yard, a truck pour is almost always the better value. The break-even point is roughly 0.5 to 1 cubic yard, depending on local ready-mix pricing and whether you already own a mixer.
How many bags fit on a pallet?
Most pallets hold 42 to 56 80-lb bags (about 56 bags for 60-lb). Buying a full pallet often saves 10 to 15 percent over single bags, and some stores offer free delivery with a full pallet order. If your job needs more than 40 bags, price a pallet before buying individually.
Bag count for the most common project sizes
| Project | Thickness | Cu yd needed | 80-lb bags | 60-lb bags |
|---|---|---|---|---|
| 4 x 8 ft pad | 4 in | 0.40 | 18 | 24 |
| 10 x 10 ft patio | 4 in | 1.23 | 56 | 74 |
| 12 x 12 ft patio | 4 in | 1.78 | 81 | 107 |
| 10 x 20 ft driveway pad | 4 in | 2.47 | 112 | 148 |
| 20 x 20 ft garage floor | 4 in | 4.94 | 223 | 297 |
| 20 x 20 ft garage floor | 6 in | 7.41 | 334 | 445 |
How to mix bagged concrete correctly
Water ratio is critical. Most 80-lb bags call for 0.5 to 0.6 gallons of water per bag (roughly 2 to 2.5 quarts). Too much water weakens the mix significantly: adding just one extra quart per bag can drop compressive strength by 10 to 15 percent. For best results, add about three-quarters of the water first, mix until lumps are gone, then add the remaining water a little at a time until the mix slides off a shovel cleanly but holds its shape. Do not add water to adjust a batch after it has begun to set.
How quickly does bagged concrete cure?
Bagged concrete typically reaches initial set in 30 to 60 minutes depending on temperature and humidity. It reaches about 70 percent of full strength after 7 days and full design strength (usually 4,000 psi for standard bags) after 28 days. Keep fresh pours moist for at least 7 days by covering with plastic sheeting or a curing compound to prevent rapid surface drying, which causes cracking. Do not pour in temperatures below 40 degrees Fahrenheit or above 90 degrees Fahrenheit without special precautions.
Ordering tips to avoid running short or wasting bags
When buying bags, always round up to the next full bag after adding your waste allowance. You cannot add a partial bag and partial bags cannot be returned once opened. For projects near a round number of cubic yards, the 10 percent waste allowance is enough. For jobs with lots of corners, odd angles, or footings with variable soil depth, use 15 percent. Store unopened bags off the ground on pallets or planks; concrete bags absorb moisture through the paper skin and will partially set in the bag if left on damp ground for more than a day or two.
What PSI do you need and which bag to choose?
Standard bagged concrete from major brands (Quikrete 5000, Sakrete, similar) delivers 4,000 to 5,000 psi compressive strength at 28 days, which meets or exceeds the 3,500 psi minimum for residential slabs, driveways, and footings. High-strength bags (labeled 5000 psi or above) cure faster and are useful when you need to strip forms or load the slab sooner. Fiber-reinforced bags include polypropylene fibers that help control shrinkage cracking in slabs. For posts and fence footings, a fast-setting no-mix formula (pour dry into the hole, add water on top) is convenient but yields lower strength, typically 2,000 to 4,000 psi; check the label and use standard mix for structural footings.
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Need to know the total volume first? See how much concrete you need for the formula by slab size.