Concrete Calculator

Concrete Calculation Formulas for Contractors

Estimating concrete volume is one of the most fundamental skills for any contractor. Whether you are pouring a driveway slab, setting footings for a residential foundation, or filling sonotube columns for a deck, accurate volume calculations prevent costly over-orders and dangerous short-pours.

Common Concrete Project Types

• Slabs & Driveways: Typically 4 inches thick for residential, 6 inches for heavy traffic. Use the rectangle formula: L x W x D / 27.
• Footings: Continuous footings for foundations are usually 12-24 inches wide and 6-12 inches deep. Calculate as a long rectangle.
• Columns & Piers: Round forms (sonotubes) use the cylinder formula: pi x r^2 x height. Common diameters are 8, 10, and 12 inches.
• Stairs: Each step adds incrementally more concrete. The total volume is the sum of all individual step volumes.

Exam Relevance

Concrete volume calculations appear on the Florida General Contractor exam under Project Management Part E (Construction Methods). You will be expected to convert between inches and feet, calculate volumes for different shapes, and convert cubic feet to cubic yards. Practice these formulas until they are second nature.