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Bagged concrete is the right choice for small projects — post holes, repair patches, steps, and slabs under half a yard. Here is everything you need to know about bag sizes, yields, and when to switch to ready-mix.
One cubic yard requires approximately 45 bags of 80 lb concrete, 60 bags of 60 lb, or 72 bags of 50 lb. For any project over 1 yard, ready-mix is almost always more economical.
| Slab Size | Thickness | 80 lb Bags | 60 lb Bags | Bag Cost (80 lb @ $7.50) |
|---|---|---|---|---|
| 2 x 2 ft | 4 in | 3 | 4 | $22.50 |
| 4 x 4 ft | 4 in | 9 | 12 | $67.50 |
| 6 x 6 ft | 4 in | 21 | 27 | $157.50 |
| 10 x 10 ft | 4 in | 62 (w/waste) | 83 | $465 |
| 10 x 10 ft | 6 in | 92 (w/waste) | 123 | $690 |
| 12 x 12 ft | 4 in | 89 (w/waste) | 119 | $667.50 |
| Post hole 10" x 3 ft deep | Round | 2 | 3 | $15 |
| Post hole 12" x 4 ft deep | Round | 3 | 4 | $22.50 |
In 2026, an 80 lb bag at a big-box store runs $7-$9. That means one cubic yard of bagged concrete costs roughly $315-$405 in materials alone — before labor. A cubic yard of ready-mix delivered costs $130-$190. The break-even point is around 0.5-1 cubic yard, depending on your local ready-mix prices and short-load fees.
For post holes and small pours, you can mix directly in the hole (dry-pack method) or in a wheelbarrow. For slabs, use a rented electric mixer for batches larger than 3-4 bags. Standard mix ratio is about 0.45-0.55 quarts of water per pound of dry mix. Less water = stronger concrete. Do not add extra water to make mixing easier — it weakens the final product.
A 10x10 slab at 4 inches thick requires 1.23 cubic yards of concrete. At 0.60 cubic feet per 80 lb bag, that is 56 bags before waste. With a 10% waste factor, order 62 bags. At 6 inches thick you will need 84 bags (92 with waste).
A 10-inch diameter hole 2.5 feet deep needs about 1.5 bags of 80 lb Quikrete. A 12-inch hole 3 feet deep needs about 2 to 2.5 bags. A 12-inch hole 4 feet deep needs about 3 bags. Use our round column calculator above for any diameter and depth.
An 80 lb bag of standard concrete mix yields approximately 0.60 cubic feet when properly mixed. This is about 0.022 cubic yards. You need roughly 45 bags of 80 lb concrete to make one cubic yard.
For projects under 0.5 cubic yards, bags are usually cheaper. Ready-mix becomes more cost-effective above 1 yard. One cubic yard of ready-mix costs $130-$190 delivered, while the same volume in 80 lb bags costs $315-$405 in materials alone at retail prices.
Technically yes, but it is not practical for anything over a small patch. A standard 12x20 driveway at 5 inches thick needs about 185 bags of 80 lb concrete — that is a lot of mixing. Use ready-mix for any driveway project.