Concrete Block Calculator: Estimate Blocks & Mortar Needs

Calculate Your Concrete Block & Mortar Requirements

Typical mortar joint is 0.375 inches (3/8").
%
Recommended: 5-10% for cuts and breakages.

Accurately calculate the exact number of concrete blocks and mortar required for your construction project. Whether you're building a foundation, a garden wall, or an entire structure, our free block estimator helps you plan effectively, saving time and preventing material waste.

Formula:

Formula for Concrete Blocks

The calculation estimates the number of blocks by dividing the total wall area by the area covered by a single block, including mortar joints. A waste factor is then applied.

Total Blocks = CEILING [ (Wall Length × Wall Height) / ((Block Length + Mortar Gap) × (Block Height + Mortar Gap)) × (1 + Waste Percentage / 100) ]

  • Wall Length (Lw): Total length of the wall(s) to be constructed.
  • Wall Height (Hw): Total height of the wall.
  • Block Length (Lb): Length of one individual concrete block.
  • Block Height (Hh): Height of one individual concrete block.
  • Mortar Gap (G): Thickness of the mortar joint (typically 0.375 inches or 10 mm).
  • Waste Percentage: An additional percentage (e.g., 5-10%) to account for cuts, breakages, and errors.

Note: Ensure all length, height, and gap inputs are converted to a consistent unit (e.g., inches) before calculation.

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