SuperCalcBrowse
SuperCalc

Concrete Quantity Calculator

Calculate concrete volume for slabs, cylinders, and foundations

Dimensions

Concrete Needed

Volume (Cubic Yards)
0.00
yd³
Volume (Cubic Feet)
0.00
ft³

Bags Needed

60lb Bags
0
≈ 0.45 ft³ per bag
80lb Bags
0
≈ 0.60 ft³ per bag

Note: These calculations provide estimates. Always order 5-10% extra to account for waste and spillage.

How to Calculate Concrete Quantity

Calculating the correct amount of concrete is crucial for any construction project. Whether you're pouring a slab, setting post footings, or building a retaining wall, accuracy prevents expensive waste or stressful shortages.

The Basic Formula

Concrete is measured in volume (cubic feet or cubic yards). The basic formula for a rectangular slab is:

Length (ft) × Width (ft) × Thickness (ft) = Volume in Cubic Feet

Why Cubic Yards?

Most ready-mix suppliers sell concrete by the cubic yard. One cubic yard equals 27 cubic feet. To convert your result, simply divide cubic feet by 27.

Bagged Concrete vs. Ready-Mix

For smaller projects (under 1 cubic yard), using pre-mixed bags is often easier. Our calculator estimates the number of bags you'll need based on standard sizes:

  • 60lb Bag: Yields approximately 0.45 cubic feet
  • 80lb Bag: Yields approximately 0.60 cubic feet

Tips for Success

  • Prepare the Subgrade: Ensure your base is compacted and level to avoid cracking.
  • Account for Waste: We recommend adding 5-10% to your total to account for uneven ground and spillage.
  • Safety First: Wet concrete is caustic. Always wear gloves, long sleeves, and eye protection.