CalculatorEnter your measurements below and it works the answer out.
Area divided by coverage, plus 5% waste, rounded up to whole units. Enter what you measured and pick how it is sold.
The arithmetic. Work out the area, divide by what one unit covers, add 5% waste, round up. Nothing more than that — the value of the page is the coverage figures and the waste allowance, both of which are stated here rather than hidden inside the tool.
Why the waste allowance is 5%. A modular brick with a 3/8 inch mortar joint occupies 8 by 2 2/3 inches of wall face, which is 0.1458 square feet — so 6.86 bricks to the square foot. A standard 8 by 8 by 16 block occupies 8 by 16 inches of face, which is 0.889 square feet, so 1.125 blocks. Both figures are the joint size and the face size, nothing more.
How it is sold. Brick is sold by the cube, usually 500 or so, and block by the pallet. Five per cent covers breakage, which is real with brick and unavoidable with cuts.
Measure the openings honestly. Deduct large openings — a garage door, a picture window, a stairwell — and ignore small ones. Cutting a sheet or a board around a normal door wastes more material than the opening saves, which is why trades quote gross area and let the waste allowance absorb it.
Round up to how it is sold. A calculator that tells you 6.3 sheets is not finished. Everything below is rounded up to whole units, because that is what you can actually buy.
Divide your area in square feet by the coverage of one unit, then add 5% and round up. At 0.1458 sq ft each, a 200 sq ft job needs 1441.
5% is what this calculator adds. A modular brick with a 3/8 inch mortar joint occupies 8 by 2 2/3 inches of wall face, which is 0.1458 square feet — so 6.86 bricks to the square foot. A standard 8 by 8 by 16 block occupies 8 by 16 inches of face, which is 0.889 square feet, so 1.125 blocks. Both figures are the joint size and the face size, nothing more.
6.86 modular bricks with a 3/8 inch joint. The number comes straight from the face size: a modular brick plus its joint occupies 8 by 2 2/3 inches, and there are 144 square inches in a square foot.
1.125 for a standard 8 × 8 × 16 in block, because each one covers 8 by 16 inches of wall face. A 100 square foot wall takes 113 blocks before breakage.