Concrete Block Calculator
Estimate blocks, mortar, and cost for your wall project
Wall Dimensions
Block Size & Cost
Blocks Required
Blocks needed = Wall area ÷ Block face area (always rounded up to whole blocks)
Waste Allowance
Industry practice often adds 5-10% extra blocks to cover cutting, breakage, and layout complexities. This is applied after the initial calculation.
Mortar Estimate
Approximately 3 bags of mortar per 100 blocks (rule of thumb). Actual requirements vary by mortar type, joint thickness, and workmanship.
Block Sizes
Standard 8×8×16 CMU is common in the US. Actual dimensions are typically 3/8″ less than nominal to account for mortar joints (e.g., 7-5/8″ × 7-5/8″ × 15-5/8″ actual).
Disclaimer: These are estimates only. Consult local building codes and a professional for structural requirements.