Concrete Block (CMU) Calculator
Block count, courses, mortar and grout for a concrete block wall, with the exact blocks-per-square-foot arithmetic shown.
Concrete Block (CMU) Calculator
Blocks, mortar and grout for a wall. The block count is exact arithmetic; the mortar is not, and this is explicit about which is which.
| Net wall area | — |
|---|---|
| Blocks per ft² | — |
| Blocks (with waste) | — |
| Courses | — |
| Mortar (approx) | — |
| Grout (approx) | — |
Exact: a nominal 8×16 block occupies 8″ × 16″ = 128 in²
of wall face including its mortar joint, so one square foot (144 in²) takes 144 ÷ 128 =
1.125 blocks. Courses are wall height ÷ nominal block height. That arithmetic does not vary.
Approximate: mortar is estimated at about three 80 lb bags of mix per 100 blocks, and grout at
roughly 0.9 ft³ per grouted cell per 8 ft of height. Both move with joint thickness, block
absorption, the mason's hand and the weather. Reinforcing steel, bond beams, lintels and cleanouts
are not counted here, and grout spacing is a structural decision that belongs to the engineer of
record, not to this page.