Construction Tool
Brick & Block Calculator
A precise masonry calculator that determines the total number of bricks, retaining wall blocks, or concrete cinder blocks needed based on wall dimensions and mortar gap sizes.
Wall Dimensions
Brick/Block & Mortar Size
How does mortar size change the block count?
In masonry, the true size of a block is technically its nominal (physical) size plus the size of the mortar joint bounding it on one side and top.
For example, standard modular bricks in the US are roughly 8" × 2.25". But with a standard 3/8" (0.375") mortar joint, the effective laid size becomes 8.375" × 2.625". Over large walls, this significantly reduces the number of bricks required compared to stacking them dry.
Standard Masonry Sizes
- Modular Brick (US): 8" L × 2.25" H
- Standard Cinder Block (CMU): 16" L × 8" H (actual is often 15.625" × 7.625" to allow for 3/8" mortar)
- Metric Brick (UK/AUS): ~ 215mm L × 65mm H
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