Wall area
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Masonry · step 1 of 3
Block wall calculator
How many concrete blocks your wall needs — then carry the count straight into grout fill and mortar. Standard 16×8 in block, openings and waste included.
Wall size
FIG. 01required
required
Based on standard 16×8 in nominal block (incl. 3/8 in mortar joint) — about 1.125 blocks per ft² of wall face. Subtract door and window openings.
How this is calculated
Multiply wall length × height for the face area, subtract openings, then multiply by about 1.125 blocks per square foot (standard 16×8 in block). This calculator does it and adds a waste margin. A 20×8 ft wall needs roughly 190 blocks.
blocks = (length × height − openings) × 1.125 × (1 + waste%)
This is step one of the block-wall workflow. Next: grout to fill the cores, then mortar to lay the block. Pouring a footing under the wall? Use the footing calculator.
FAQ
How many concrete blocks do I need for a wall?
Multiply wall length × height for the face area, subtract openings, then multiply by about 1.125 blocks per square foot (standard 16×8 in block). This calculator does it and adds a waste margin. A 20×8 ft wall needs roughly 190 blocks.
What size is a standard concrete block?
A standard CMU is nominally 16 inches long × 8 inches high × 8 inches wide, which includes the 3/8-inch mortar joint. That nominal face is why about 1.125 blocks cover each square foot of wall.