Concrete Slab Calculator
Enter slab dimensions and thickness to get cubic yards, bag count, and material cost.
Concrete needed — cubic yards
Slab area —
80 lb bags —
Est. total cost —
Ready-mix delivery is economical above ~2 cubic yards. Short-load fees apply under 4 yards.
How to use this calculator
- Measure your slab length and width in feet
- Select thickness — 4" for patios, 6" for driveways and garage floors
- Choose concrete type and optional rebar for a total cost range
Thickness recommendations
- 4 inches — Sidewalks, patios, shed pads (foot traffic only)
- 5 inches — Driveways with light vehicles, RV pads
- 6 inches — Standard driveways, garage floors, heavy loads
Ready-mix vs bagged concrete
Bagged 80 lb mix (~0.022 cu yd each) works for pours under 1 cubic yard. Ready-mix delivery saves 30–40% on projects above 2 cubic yards but short-load fees ($75–$150) apply when ordering under 4 yards.