About & methodology

Concrete Calculator is a free tool for estimating how much concrete or aggregate a project needs — in cubic yards, bags, and tons. No sign-up; the math runs in your browser.

Concrete volume

• Slabs, footings, and walls: length × width × thickness (in feet) = cubic feet.
• Round columns: π × radius² × height.
• Cubic yards = cubic feet ÷ 27. A 10% waste allowance is added by default.
• Bag counts use standard yields: 80 lb ≈ 0.60 ft³, 60 lb ≈ 0.45 ft³, 40 lb ≈ 0.30 ft³.

Aggregate & landscape material

Area × depth gives the volume in cubic yards; a per-material density (pounds per cubic yard) converts that to tons, which is how bulk gravel, sand, and stone are sold. Densities are typical dry, loose values — real weight varies with moisture and compaction.

Important

These are planning estimates, not engineering specifications. For structural pours, large orders, or anything load-bearing, confirm with your ready-mix supplier or a professional.