Concrete Slab Calculator (Cubic Yards & Bags)
calc_concrete_slabRead-only
Estimate ready-mix cubic yards or the number of 80 lb bags for a rectangular slab, patio or driveway. Formula: Cubic yards = Length(ft) × Width(ft) × Thickness(in)/12 ÷ 27 × (1 + waste%). Bags = cubic feet ÷ bag yield.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| depth_in | No | Thickness (in); default 4 | |
| width_ft | No | Width (ft); default 10 | |
| length_ft | No | Length (ft); default 20 | |
| waste_pct | No | Waste allowance (%); default 10 | |
| bag_yield_cf | No | Bag yield (cu ft/bag); default 0.6 |