A brick wall is one of the most satisfying things to build, and one of the easiest to mis-order. Bricks are cheap individually, so the cost of a mistake looks small — until the delivery truck has gone, the wall is three courses short, and the next batch of bricks is a slightly different shade. Working out the number before you order takes ten minutes and saves all of that. This guide shows how, with a worked example.
Start with the size of one brick
Bricks come in different sizes, so the first step is knowing the size you are using. A standard modular brick has a face 8 inches long and 2.625 inches high, which covers 0.145833 square feet once the mortar joint is included. That works out to 6.86 bricks per square foot of wall.
If you are using a different brick, measure it yourself: lay the brick with its mortar joint and measure the face, length times height, in inches, then divide by 144 to get square feet. The rest of the method is exactly the same, just with your number instead of 6.86. Never guess the brick size — a quarter of an inch per brick adds up to a whole course over a long wall.
Measure the wall area
Measure the length and the height of the wall in feet and multiply them to get the area in square feet. If the wall has a door or a window in it, measure the opening and subtract its area — you do not need bricks where the opening is. For a wall with a sloping top, such as a gable, split it into a rectangle and a triangle, work out each part separately, and add them together.
Measure the real wall, not the drawing. Walls are rarely exactly the size on the plan, and a few inches over a long wall is several square feet of bricks. If the wall is already partially built or marked out, measure that.
Worked example: an 80 square foot wall
Take a garden wall with an area of 80 square feet, built with standard modular bricks at 6.86 bricks per square foot. Multiply 80 by 6.86 and you get 548.8 bricks for the wall itself. Then add a waste allowance for cuts and breakages — 5% is a sensible figure for a straight wall. 548.8 plus 5% is 576.24, so order 576 bricks.
Waste is not optional. Bricks break, corners need cutting, and half bricks at the ends of courses all come out of your allowance. A straight wall needs about 5%; a wall with curves, piers or a lot of openings needs more, because there is more cutting. Rounding up to the nearest whole number is part of the job — suppliers do not sell part of a brick.
How much mortar do you need?
Bricks are only half the order — the mortar matters too. As a rule of thumb, one 60 lb bag of mortar covers about 35 bricks. For our wall of 576 bricks, divide 576 by 35 and you get 16.46 bags, so buy 17 bags. That rule of thumb is for standard joints; wider joints or a rougher brick use more mortar, so keep a spare bag if you are unsure.
Mix mortar in small batches. Mortar that sits too long goes stiff and cannot be reworked properly, and wasted mortar is wasted money. If you are new to bricklaying, mix less per batch than you think you need — you can always mix more, but you cannot un-mix a barrow that has gone off.
Bricks or blocks?
For a structural wall or a large area, concrete blocks are often faster and cheaper than bricks. A standard 8 x 8 x 16 inch block plus its mortar joint covers about 0.95 square feet, so a 10 foot by 4 foot wall needs about 42 blocks before waste. Blocks are usually rendered or clad, while bricks are the finished face — the choice is about the look you want and the structure you need, not just the count. If the wall holds back soil or supports a load, check local building rules for reinforcement and footing depth before you build.
How to use the calculator
Open the brick calculator and enter your wall length and height, choose your brick size, and set the waste allowance. It shows the brick count and the mortar bags, including the 5% waste in our example. If you are pricing the whole job, the concrete calculator works out the footing underneath the wall, and the cement calculator covers the mix if you are batching your own mortar. For a block wall instead, the concrete block calculator does the same job for blocks.
Before you order
Order all the bricks at once, from the same batch. Brick colour varies between batches, and a wall built from two batches will show a line where the batch changed. Keep a few spare bricks after the job — a matching brick is hard to find later, and a small repair with a mismatched brick stands out. Store bricks off the ground and covered, so they stay dry and clean until you need them.
Measure the brick, measure the wall, multiply, add your waste, and order once. That is the whole job — and it is the difference between a wall that finishes on the day and one that waits for a second delivery in a different shade.