Concrete Calculator — How Much Concrete Do I Need?
Enter your dimensions for an instant answer — the exact quantity to buy (waste included), a material cost, and an estimated installed cost. Change any figure to update the result live.
Your project
Standard size shown by default. Change any value — the answer recomputes instantly.
You need
1.9cubic yards (ready-mix)
Exact need: 1.78 cubic yards (ready-mix) · plus 7% waste allowance
Material cost
$237.5–$313.5
Installed (US avg)
$788–$1,059
Shopping list
| ITEM | QTY | PRICE RANGE |
|---|---|---|
| cubic yards (ready-mix) | 1.9 | $237.5–$313.5 |
| Estimated material total | $237.5–$313.5 |
Alternative buy formats
- 86 × 80 lb bags — $473–$688
- 115 × 60 lb bags — $517.5–$805
Material spec & worked example
Density
145 lb/ft³
Waste allowance
7%
Typical price
$125–$165 cubic yards (ready-mix)
12 ft × 12 ft, 4 in thick: you need 1.78 cubic yards (ready-mix) (buy 1.9 with waste), about $237.5–$313.5 in materials. See how we calculate this →
Popular sizes
Installed cost by state
See a regionally-adjusted installed estimate — materials, labor, total.
View cost by state →Frequently asked
How much concrete do I need for a 12x12 slab?
A 12 ft × 12 ft slab at 4 inches thick needs about 1.8 cubic yards of concrete (48 cubic feet + waste). Use the calculator above to match your exact dimensions.
How many 80 lb bags of concrete in a cubic yard?
It takes 45 bags of 80 lb concrete mix to make one cubic yard, since each 80 lb bag yields about 0.6 cubic feet.