Brick is ordered by the thousand and delivered by the cube, but walls are measured in feet — this calculator bridges the two. Give it the wall's length and height and the brick you intend to lay, and it returns the count, including the mortar joints that quietly consume a surprising share of every wall, plus the waste allowance that keeps a broken or badly-cut brick from stopping the job.
Why the mortar joint does the counting
Nobody lays bricks touching. A standard 3/8 inch mortar joint separates every course and every brick, so the patch of wall each brick actually covers is the brick's face plus one joint on its length and one on its height. A modular brick's face is 7⅝ × 2¼ in, but it covers 8 × 2⅝ in of wall — 21 square inches — so a square foot of wall takes 144 ÷ 21 ≈ 6.86 modular bricks. Estimate from the naked brick size instead and you under-order by roughly a fifth, which is why so many first-time brick projects end with a second, mismatched delivery.
The five sizes on the menu
Modular (7⅝ × 2¼ in) is the modern default, sized so courses and joints add up to round numbers of feet. Standard (8 × 2¼ in) is the older traditional face brick. Queen (7⅝ × 2¾ in) is a little taller per course, so walls rise faster with fewer bricks. King (9⅝ × 2⅝ in) covers more wall per unit again, and Utility (11⅝ × 3⅝ in) is the big structural unit used where speed matters more than fine joints. All five are face dimensions; whichever you choose, confirm the actual size with your supplier, because regional variations exist and a quarter-inch difference compounds across a wall.
Openings, wythes and waste
The count assumes a solid, single-wythe wall — one brick thick. For a wall with a large door or window, subtract the opening's area from the wall before you start (small openings are usually ignored; the bricks “saved” cover the extra cuts around them). A structural double-wythe wall needs roughly twice the bricks. The waste allowance — 10% by default — covers breakage in transit, cuts at corners and ends, and the handful of bricks in every cube that are chipped or off-colour; go to 15% for lots of cutting, diagonal work or a first-time bricklayer.
Worked example
The defaults are a garden wall 10 ft long and 8 ft high in modular brick: 80 ft² × 6.857 bricks per ft² = 549 bricks exact, and 604 bricks with the 10% allowance — a little over one standard cube. Switch the size to Utility and the same wall needs only about 226 bricks, which is the whole appeal of the big units.
How to use this tool
- Measure the wall's length and height in feet; subtract any large door or window openings.
- Choose the brick size you will actually buy — check the supplier's stated dimensions.
- Keep the 10% waste allowance unless the wall is heavily cut, in which case use 15%.
- Read the “with waste” count and round up to your supplier's pack or cube size.
- For a two-wythe (double thickness) wall, double the final count.
Mortar to go with them
As a planning figure, a standard 80 lb bag of mortar mix lays roughly 35–40 modular bricks with 3/8 in joints, so the example wall above wants about 15 bags — but mortar estimating is famously rough, because joint fullness and waste vary by layer. Buy bags in stages if the supplier allows returns of unopened stock, keep them dry, and never re-temper mortar that has started to stiffen beyond the manufacturer's stated window: weak mortar is the one saving that quietly ruins a wall.