NYC Concrete Calculators · 5 Boroughs Ready-Mix & Flatwork Estimation
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Concrete Slab & Footing Calculator

Calculate the exact concrete volume required for slabs, footings, patios, and walkways in cubic yards, cubic feet, and cubic meters, plus premixed bag counts.

Project Dimensions

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Total Concrete Required (with waste)
2.72 yd³
Order ready-mix rounded to nearest 0.25 yd³
Surface Area: 200.0 sq ft
Volume in Cubic Feet: 73.33 ft³
Volume in Cubic Meters: 2.08 m³
Included Waste Allowance: 0.25 yd³ (10%)
Premixed 80 lb Bags Needed: 123 bags
Premixed 60 lb Bags Needed: 163 bags
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How to Calculate Concrete Volume: Formula & Step-by-Step Example

Concrete is specified and ordered in cubic yards. One cubic yard is a 3-dimensional cube measuring 3 feet by 3 feet by 3 feet, totaling 27 cubic feet (or 46,656 cubic inches).

The Concrete Volume Formula

Volume (Cubic Feet) = Length (ft) × Width (ft) × (Thickness in inches ÷ 12)
Volume (Cubic Yards) = Volume (Cubic Feet) ÷ 27
Total with 10% Waste = Volume (Cubic Yards) × 1.10

Worked Example for an NYC Sidewalk Flag

Suppose you are pouring four standard NYC sidewalk flags, each measuring 5 feet by 5 feet, for a total run of 20 feet long by 5 feet wide, at the standard 4-inch sidewalk thickness:

  1. Surface Area: 20 ft × 5 ft = 100 square feet.
  2. Convert Thickness to Feet: 4 inches ÷ 12 = 0.333 feet.
  3. Cubic Feet: 100 sq ft × 0.333 ft = 33.33 cubic feet.
  4. Convert to Cubic Yards: 33.33 cu ft ÷ 27 = 1.23 cubic yards.
  5. Add 10% Waste Buffer: 1.23 cu yds × 1.10 = 1.36 cubic yards.
NYC Ready-Mix Delivery Thresholds
Most NYC ready-mix suppliers have minimum delivery thresholds of 3.0 to 4.0 cubic yards. Smaller orders incur a short-load charge (typically $100 to $250). For small flag repairs, hand mixing with premixed bags may be preferable. Call (646) 922-9144 for local supplier and contractor advice.
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