Bricks or blocks, mortar, cement and sand for walls and foundations.
One wythe is a single row of bricks thick. Double is two, back to back.
The gap between bricks. Accepts fractions — 3/8 works.
Cement to sand by volume. 1:4 is general purpose.
Extra to order for breakage and cuts. 5% is typical.
Nothing to work out yet
Enter values for Wall Length, Wall Height, Mortar Joint Thickness.
Wall area is length × height less the door and window openings you enter — you do not lay brick through a doorway. Each unit is measured with one mortar joint added to its length and height, so the joint thickness you type changes how many bricks fit the wall. A double wythe wall is two leaves thick and takes twice the brick. Mortar is whatever is left once the bricks are taken out of the wall volume; that volume is raised by 1.30 for dry bulking, split by your cement:sand ratio, and the cement converted to 40 kg bags. Water is then quoted at half the weight of that cement, which is an allowance for what to have on site rather than a mix design — mortar is gauged by feel, and dry bricks in summer drink far more than a damp block in winter.
A single-wythe wall 10 metres long and 2.4 metres high, in standard bricks with a 3/8 inch joint and a 1:4 mortar mix. That is 24 m² of wall face, and the calculator returns 1,693 bricks, 0.4 m³ of mortar, 4 bags of cement, 0.67 tonnes of sand and about 75 litres of water.
The number that does the work is on line two of the working: one unit plus its joint is 213 × 67 mm, or 0.0142 m². Not 203 × 57 mm, which is what the brick itself measures. Every brick in a wall carries half a joint on each side and half on top and bottom, so the area it really occupies includes the mortar around it. Divide 24 m² by that and you get 1,692.1, which rounds up to 1,693.
Change the joint from 3/8 inch to 1/2 and the count drops, because each brick now occupies more wall. That is not a rounding artefact — it is the reason two bricklayers quoting the same wall can order different quantities.
Counting bricks by their own size rather than by their size plus a joint. On this wall that error is about 190 bricks — you would order 1,500 and be nearly 200 short on the last course, which is exactly when a merchant delivery becomes a second delivery.
The other one is wythes. A single wythe is one brick thick; a double is two, back to back, and it does not just double the bricks — it changes the mortar volume as well, because the collar joint between the two leaves has to be filled too. If you are building a boundary wall rather than a skin, check that dropdown before you order.
Bricks by the count, cement by the bag, sand by the tonne. Sand is the one worth being careful about: the calculator works in volume and converts at 1.6 tonnes per m³ to give you a weight, because that is how it is sold. Damp sand weighs more per cubic metre than dry, so if a load looks short against this figure, that is usually why.
The water figure is for mixing, not for ordering — it is there so you know what to have standing by. A 1:4 mix at a 0.5 water-cement ratio needs roughly half the weight of the cement in water, and running out of water halfway through a mix is its own kind of bad day.
Open "Show the working". Line one is your wall area less any openings you entered. Line two is the unit-plus-joint size, which you can measure against a brick and a tape. If those two agree with what you see on site, the rest is arithmetic.
The mortar figure is derived rather than assumed: it is the volume of the wall minus the volume of the units inside it, which is why it moves when you change the joint thickness or the unit size. A per-brick mortar rule of thumb would not do that, and would be wrong on blockwork by a wide margin.