Brick Calculator

How a brick count is actually worked out

Every brick estimate is the same three-step sum: measure the wall face, work out how much wall one brick covers once its mortar joint is included, then divide and add a waste allowance. The part people skip is the joint. A brick does not cover its own size — it covers its size plus half a joint on each side, which is why the number you get from a supplier's chart never matches the raw brick dimensions.

For a US modular brick the actual face is 7 5/8 in long by 2 1/4 in high. Add a standard 3/8 in joint to each dimension and the brick effectively occupies 8 in by 2.625 in, or 21 square inches. A square foot is 144 square inches, so 144 divided by 21 gives 6.86 bricks per square foot. That single number does most of the work in this calculator.

Worked example: a 20 ft by 8 ft veneer wall

Take the front of a garage: 20 ft long, 8 ft high, with one 7 ft by 3 ft window opening. The gross face is 20 x 8 = 160 sq ft. The window removes 21 sq ft, leaving 139 sq ft of brickwork. At 6.86 bricks per square foot that is 953 bricks before any allowance. Add 10 per cent for cuts, corner returns and breakage and you order 1,049 bricks. Mortar at the trade rule of one 60 lb bag per 40 bricks comes to 27 bags.

Note what the opening did: 21 sq ft is 13 per cent of the wall, and dropping it cut about 145 bricks from the order. On a house elevation with three or four windows and a door, ignoring openings can overstate the job by a fifth. Measure each opening, add the areas together, and enter the total.

What the joint size does to the total

Change nothing but the joint and the numbers move noticeably. With a 1/2 in joint the same modular brick occupies 8.125 in by 2.75 in, which is 22.34 square inches, or 6.45 bricks per square foot. The same 139 sq ft wall now needs 897 bricks before waste and 987 after — about 62 fewer than the 3/8 in version. Thicker joints mean fewer bricks and more mortar; thinner joints mean the opposite. If your bricklayer has a habit, ask before you order.

UK sizing works the same way in metric. A 215 x 65 mm brick with a 10 mm bed and perp joint occupies 225 x 75 mm, which is 0.016875 square metres. One square metre divided by that is 59.3 bricks, and the trade rounds to 60 per square metre for single-skin work. Multiply by two for the classic cavity wall with brick on both leaves.

Estimating mortar realistically

The one-bag-per-40-bricks rule is a planning figure, not a specification. Real consumption depends on joint thickness, whether the bricks are frogged or cored, how absorbent they are on a hot day, and how much falls off the board. If you are mixing from sand and cement rather than buying pre-blended bags, a common starting point is roughly 1 cubic yard of mortar per 1,000 modular bricks with 3/8 in joints, mixed at about 1 part cement, 1 part lime and 6 parts sand for a Type N blend.

Buy mortar in the same trip as the brick, but buy it last. Bagged mortar has a shelf life and hates damp storage, so it is better to be slightly short and top up than to have half a pallet harden in a shed over the winter.

Pallets, delivery and site logistics

Brick usually arrives banded on pallets of roughly 500, though counts run from about 450 to 530 depending on the manufacturer and brick size. Our 1,049-brick order is therefore three pallets — about 2.1 pallets of actual brick, but you cannot buy fractions, and the leftovers are your repair stock. A full pallet weighs around 1.5 tons, so check that the delivery lorry can reach where you want it and that the ground will take the weight. Placing pallets within a wheelbarrow run of the wall saves hours of double handling.

Order the whole job at once. Brick colour comes from clay chemistry and kiln position, and two batches of the same product code can be visibly different. Suppliers blend across pallets from a single production run for exactly this reason, which is impossible to replicate months later.

Limitations of this estimate

This calculator counts a single-layer wall in a running or stack bond of uniform bricks. It does not account for header courses tying two wythes together, soldier courses over openings, arches, decorative patterns such as herringbone, or corner overlaps on a wall that turns. Each of those consumes extra brick, which is what the waste allowance is loosely covering. For a complex elevation, run the calculator per wall face, add the results, then have the mason sanity-check the total before you place the order.