Brick calculator

How many bricks a wall takes, set by the brick size you're actually laying. A modular wall needs more than twice the units a utility wall does, so the size isn't a detail — it's most of the count.

01 How the math works

Brick is a coverage problem. Work out the wall's face area, multiply by the number of brick one square foot of that wall holds, add a waste factor, and round up. The figure that does the work is the coverage number, and it isn't a constant — it's set by the brick's size and the mortar joint around it.

The coverage comes straight from the brick's coursing rectangle: the exposed face plus one mortar joint on each side. A modular brick shows a 7-5/8 in by 2-1/4 in face; add the 3/8 in joint and each brick claims an 8 in × 2-5/8 in patch of wall — 21 in², or 6.86 brick to the square foot. Change the brick and that number moves a lot. A utility brick covers more than twice the wall a modular does, so the same wall takes less than half the units.

Wythes are brick thicknesses. A veneer or a garden wall one brick thick is a single wythe; a structural wall two brick thick is two, and takes twice the count. Most calculators assume one wythe without saying so, which is fine right up until you're building the wall that isn't.

02 Worked example

Take a single-wythe garden wall, 20 ft long and 8 ft tall (6.10 m × 2.44 m), laid in modular brick with standard 3/8 in joints. The face area is 160 ft² (14.86 m²).

At 6.86 brick per ft², that's 160 × 6.86 = 1,098 brick before waste. A straight run of full brick wastes little, so add the 5% standard masonry allowance: 1,153 brick to order.

Now swap the size and hold everything else. The same wall in queen brick takes 160 × 5.76 = 922, or 968 with waste. In utility brick it's 160 × 3.0 = 480, or 504 with waste. Same wall, same waste — and the modular order is more than double the utility order, 1,153 against 504. Reading the count off the wrong size is the most expensive mistake a brick estimate can make, and it's the one no flat calculator warns you about.

03 When this calculator is wrong

The coverage figures assume a 3/8 in mortar joint, the standard for modular brick. Widen the joint and the count drops, because a fatter joint means each brick claims more wall. At a 1/2 in joint the modular figure falls from 6.86 to 6.45 brick per ft² — that's 144 ÷ ((7-5/8 + 1/2) × (2-1/4 + 1/2)) — a 6% cut in brick and a matching rise in mortar. On the 160 ft² wall above, that's about 69 fewer brick. Set the joint to what you'll actually strike, not what the default assumes.

• "Jumbo," "king," and "oversize" are marketing names, not sizes. The utility brick here is the 4×4×12 unit most often sold as jumbo, but producers hang those labels on different dimensions. The coverage follows the actual face, so measure the brick — or read the box — before you trust a name. A "king" brick counted as a modular over-orders by roughly a third.
• The default 5% waste is for a straight, solid wall in full brick. Corners, returns, and every door or window opening add cut brick, and cut brick is waste — the offcut rarely fits the next spot. On a wall with several openings or a lot of corners, real waste runs 10% or more. The 5% is right for a plain run and low for anything busy.
• Openings aren't subtracted. The calculator counts the full face area. A wall with a wide garage opening or a bank of windows over-orders unless you take those areas off first — figure each opening in square feet, subtract it from the wall area, and re-run.
• It's brick only, not the mortar. The count doesn't size mortar, wall ties, or reinforcement. Those are separate figures, and tie spacing for anchored veneer is set by code — check your local requirement rather than a rule of thumb.

04 What to do with the result

Order the rounded-up count, and buy it in one delivery from one run. Brick is fired in batches and colour drifts between them — a second order weeks later can arrive a shade off, enough to read as a band across a wall in daylight. A few spare brick on a pallet cost little next to re-facing a section to hide a colour break, so round up to the full order and keep the leftovers as attic stock.

Brick is sold by the unit but delivered on pallets or straps of several hundred, so the practical ordering step is the pack, not the single brick. Take the count to your supplier and let them round to their pack size — and confirm the brick's size and joint with them, since that's what set the number in the first place.

05 Common questions

How many bricks do I need per square foot?

For a single-wythe wall at a 3/8 in joint: 6.86 modular brick per ft², 5.76 queen, or 3.0 utility (BIA Technical Note 10). Multiply your wall's face area by the figure for your brick, then add waste.

What's the difference between modular, queen, and utility brick?

Size. Modular shows a 7-5/8 × 2-1/4 in face, queen a taller 7-5/8 × 2-3/4 in, and utility a much larger 11-5/8 × 3-5/8 in. Bigger faces mean fewer brick: utility covers a wall at 3.0 brick per ft² against modular's 6.86, less than half.

How many bricks are in a square metre?

73.8 modular brick per m², 62.0 queen, or 32.3 utility, at a 3/8 in joint. These are the imperial coverage figures converted with the exact square-foot-to-square-metre factor.

Does the mortar joint change how many bricks I need?

Yes. The count assumes a 3/8 in joint. Widen it to 1/2 in and modular coverage drops from 6.86 to 6.45 brick per ft² — fewer brick, more mortar. The joint is part of the coursing, so it moves both numbers at once.

How much extra brick should I buy for waste?

5% for a straight, solid single-wythe wall in full brick. More for anything with corners, returns, or openings, where cut brick pushes real waste to 10% or higher. The offcut from a cut brick rarely fits the next course, so it counts as waste.