Verified Mathematical Model & Formulation
Concrete (yd³) = Length × Width × Thickness / 324 × (1 + Waste%) Rebar Length (ft) = Grid lines × Span length × 1.15 lap splice factor
Calculates concrete volume alongside rebar reinforcement lengths spaced at standard 12, 16, or 18-inch on-center grids with 15% overlap splices.
Configurable Parameters & Standard Units
- Slab Length: (Default: 24 ft)
- Slab Width: (Default: 24 ft)
- Slab Thickness: (Default: 5 in)
- Rebar Grid Spacing: (Default: 18 in)
Standard Worked Example & Practical Verification
Scenario: Estimating a 24 ft by 24 ft garage slab at 5-inch thickness with #4 rebar at 18-inch spacing.
Calculated Solution
9.78 Yards Concrete & 45 Rebar Sticks (20-ft)
Practical Takeaway: Order 10.0 cubic yards of 4,000 PSI concrete mix to cover edge thickenings.
Frequently Asked Questions
Do I need rebar in a 4-inch slab?
While fiber mesh can help reduce micro-cracking, steel rebar (#3 or #4) or welded wire fabric provides essential tensile strength when the subgrade shifts.