Concrete Calculator

Estimate concrete volume in cubic yards or cubic meters and 80 lb bags for a rectangular pour.

Concrete Calculator helps you estimate concrete volume (and bags) for a rectangular slab or footing. Enter length, width, thickness, and waste, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Concrete calculator does Concrete Calculator is built for materials, areas, volumes, and jobsite estimates. Estimate concrete volume (and bags) for a rectangular slab or footing. You enter length, width, thickness, and waste, then Simple Calculators computes the result instantly. Formulas match common contractor and DIY references for rectangular and simple shapes. How the math works US: cubic feet = length × width × (thickness in inches ÷ 12), and cubic yards = cubic feet ÷ 27. Metric: cubic meters = length × width × (thickness in cm ÷ 100). 80 lb bags make about 0.60 ft³ each. The formula: Cubic yards = length × width × (thickness in inches ÷ 12) ÷ 27 × (1 + waste). Metric: cubic meters = length × width × (thickness in cm ÷ 100) × (1 + waste).