Concrete Calculator 2026
Estimate cubic yards, bags, and total cost for any concrete project. Slabs, footings, columns, and walls.
Project Type
Dimensions
Options
| Slab Size | Thickness | Cubic Yards | 80 lb Bags | Est. Cost |
|---|---|---|---|---|
| 10×10 ft | 4 in | 1.36 yd³ | 62 | $292–$416 |
| 10×10 ft | 6 in | 2.04 yd³ | 92 | $401–$581 |
| 12×12 ft | 4 in | 1.96 yd³ | 89 | $421–$598 |
| 12×20 ft | 4 in | 3.26 yd³ | 147 | $701–$989 |
| 20×20 ft | 4 in | 5.43 yd³ | 245 | $1169–$1648 |
| 20×20 ft | 6 in | 8.15 yd³ | 367 | $1604–$2319 |
| 24×24 ft | 4 in | 7.82 yd³ | 353 | $1684–$2374 |
| 30×30 ft | 5 in | 15.28 yd³ | 688 | $3119–$4459 |
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FAQs
How many 80 lb bags per cubic yard?
Approximately 45 bags of 80 lb concrete = 1 cubic yard. Each 80 lb bag yields ~0.60 ft³. Always add 10% waste.
When should I use bags vs. ready-mix?
Under 0.5 yd³ → bags are cheaper. Over 0.5 yd³ → ready-mix truck is more economical. Short-load fees apply under 8 yd³.
What PSI concrete for a driveway?
3000-4000 PSI with 4-6 inch thickness. Use 4000 PSI for heavy vehicle traffic. Always check local building codes.
Do I need rebar or wire mesh?
Wire mesh for patios/walkways (non-structural). Rebar (#3 or #4) for driveways, garage floors, structural slabs. 12-18 inch grid spacing.
What does a yard of concrete cost in 2026?
National average: $130-190/yd³ for 3000 PSI. Northeast/West Coast higher ($160-200). Southeast/Midwest lower ($120-150).
How thick should a concrete slab be?
Patios/walkways: 4". Driveways: 5-6". Garage floors: 5-6". Commercial/heavy: 6-8". Check local code.