How Many Bricks Do I Need? Wall Calculator Guide
Divide your net wall area by the face area of one brick, then add a waste allowance for cuts, joints, and breakage. A plain garden wall built from 200 by 60 mm bricks needs about 83 bricks per square metre before allowance, so a 14.4 square metre wall at a 10 percent allowance comes to 1,320 bricks. The rest of this guide shows the formula, the brick sizes that change the answer, and the mistakes that cause most short orders.
How do you calculate how many bricks you need?
The calculation has three steps, and none of them is hard — the errors come from skipping one. First, find the net wall area: multiply wall length by wall height, then subtract the area of every door, window, and opening. Second, divide that area by the face area of one brick (length times height, in the same units). Third, add a waste allowance for cutting, breakage, and mortar joints. Written out, the formula is:
Bricks = Wall area / (Brick length x Brick height) x (1 + Allowance / 100)
Units matter here. Wall area is usually measured in square metres, while brick dimensions are sold in millimetres, so convert first: divide each millimetre figure by 1,000 to get metres. A 200 mm brick is 0.200 m long, and a 60 mm brick is 0.060 m high, giving a face area of 0.012 square metres. One divided by 0.012 is 83.33, which is where the familiar "about 83 bricks per square metre" figure comes from. If you work in feet, convert the wall area first — one square metre equals 10.764 square feet — rather than mixing feet and millimetres in the same division.
The brick calculator runs exactly this formula: enter the net wall area, the brick face size, and a waste percentage, and it returns the count including the allowance. It treats the mortar joint as part of the allowance rather than as a separate deduction, which is the simpler of the two methods described below. Either method gives a sound answer, but mixing them is the most common cause of over-ordering.
Worked example: a garden wall
Take a garden wall 8 metres long and 1.8 metres high, built from 200 by 60 mm bricks, with no openings and a 10 percent waste allowance.
Step 1 — net wall area. 8 x 1.8 = 14.4 square metres. There are no doors or windows to subtract, so the net area stays 14.4.
Step 2 — face area of one brick. 200 mm is 0.200 m and 60 mm is 0.060 m, so one brick face covers 0.200 x 0.060 = 0.012 square metres.
Step 3 — bricks before allowance. 14.4 / 0.012 = 1,200 bricks exactly.
Step 4 — add the allowance. 1,200 x 1.10 = 1,320 bricks to order. If the same wall were plain and straight with almost no cutting, a 5 percent allowance would give 1,200 x 1.05 = 1,260 bricks instead.
Now add an opening to see why the deduction matters. Suppose the wall has a gate opening 1.2 metres wide and 1.8 metres high: that is 2.16 square metres, leaving a net area of 12.24 square metres. At the same brick size and 10 percent allowance, the order becomes 12.24 / 0.012 = 1,020, times 1.10 = 1,122 bricks — nearly 200 fewer than counting the wall as solid. Skipping the deduction is a fast way to pay for bricks you will never lay.
What size brick should you use in the calculation?
Brick sizes differ by country and by product, and a few millimetres per brick compounds across a whole wall. Always enter the face of the brick you are actually buying, measured from the supplier's specification, not from a generic table. The table below shows the bricks per square metre for three common sizes, both as bare faces and with a 10 mm mortar joint added to each direction (the laying module).
| Brick | Face (mm) | Bare face (per m²) | With 10 mm joint (per m²) |
|---|---|---|---|
| Common metric brick | 200 x 60 | 83.3 | 68.0 |
| UK standard brick | 215 x 65 | 71.6 | 59.3 |
| US modular brick | 194 x 57 | 90.4 | 73.2 |
The UK row explains the rule of thumb you may have heard that a standard brick wall takes about 60 bricks per square metre: that figure already includes the mortar joint (225 x 75 mm module, giving 59.3). The bare-face figure for the same brick is 71.6, which is a different number answering a different question. If you pick up a rule of thumb, check whether it counts the joint before you use it — a table and a rule of thumb that disagree are usually just measuring different things.
Should you count the mortar joint or the bare brick?
Both methods work, and the brick calculator uses the bare-face method with the joint absorbed into the allowance. The laying-module method instead enters the brick plus one joint: a 200 by 60 mm brick laid with 10 mm joints occupies a 210 by 70 mm module, covering 0.0147 square metres, or 68.0 bricks per square metre. That already accounts for the joints, so it needs only a small allowance for cutting and breakage — typically 5 percent or less.
The trap is combining the two. Entering the 210 by 70 mm module and then adding a 10 percent allowance counts the joints twice over in effect, and the order comes out roughly a fifth higher than it should be. On a 1,200-brick wall, that is about 240 extra bricks: real money, and a pallet sitting in the garden for years. Whichever method you choose, write it down next to the calculation so that anyone checking the order can see which one you used.
How much waste allowance should you add?
The allowance is a judgement about the wall, not a fixed constant. A plain rectangular wall with long straight runs and no openings wastes very little — 5 percent is enough. A typical house wall with corners, window and door openings, and a few piers lands around 10 percent. Walls with arches, curves, angled cuts, or decorative soldier courses (bricks stood on end) can justify 10 to 15 percent, because every angle produces offcuts too short to reuse.
Material matters as well. Soft, handmade, or reclaimed bricks break more in transport and during handling, so add a further 5 percent for those. The same applies if bricks will be delivered to a site with rough access or stored outdoors through wet weather. Against all of this, weigh the cost of running short: a second delivery costs money, and worse, a second batch may not match the colour of the first. Bricks vary slightly between firings, so a wall finished from two batches can show a visible band. Ordering a small surplus from one batch is cheap insurance, and keeping 10 to 20 spares afterwards covers future repairs with matching bricks.
What about double walls, piers, and openings?
A double-thickness wall (two skins of brickwork) needs twice the bricks of a single skin covering the same area — run the calculation once per leaf and add the two counts. A cavity wall works the same way: count the outer leaf and the inner leaf separately. Wall ties, insulation, and lintels are separate items and never appear in the brick count, so remember to order them on their own.
Piers are easy to miss. A freestanding pier is a small wall of its own: measure its perimeter faces and add that area to the wall total before dividing, rather than treating the pier as part of the flat run. Similarly, a wall that steps up a slope should be measured in sections — each section's length times its own height — instead of using one average height for the whole run. Both mistakes are small on paper and visible in the final bill when the order runs short near the top of the slope.
Practical tips
- Measure twice, order once. Measure length and height on site, not from a drawing alone, and subtract every opening before you touch the calculator. A drawing that shows a wall as 2.4 metres high when it is really 2.6 adds more than 8 percent to the count.
- Buy one batch. Order the full quantity, including the allowance, from a single batch so the colour stays consistent across the wall, and keep the spares from that batch for repairs.
- Check the pack size. Divide your total by the pack size your supplier actually sells — commonly 400 to 500 bricks per pack — and round up to whole packs. Confirm the pack size before ordering, not when the delivery arrives short.
- Count piers and steps separately. Piers, stepped sections, and returns each add face area that a single length-times-height figure will miss. Measure them as their own rectangles.
- Store bricks off the ground. Stack packs on level boards, keep them dry, and avoid double-stacking soft bricks. Breakage in storage is breakage you already paid for.
- Remember this is a quantity count, not structural advice. Wall thickness, ties, lintels, foundations, and lateral support decide whether a wall stands up, and those questions belong to a qualified professional, not a calculator.
Try it yourself
Enter your net wall area, brick face size, and waste allowance to get the brick count for your wall — everything runs locally in your browser, nothing is uploaded.
Frequently asked questions
How many bricks do I need per square metre?
It depends on the brick face. A 200 by 60 mm brick covers 0.012 square metres, so one square metre needs 83.3 bricks before any waste allowance. A UK standard brick of 215 by 65 mm needs about 71.6 per square metre, and a US modular brick of 194 by 57 mm needs about 90.4. Once you add a 10 mm mortar joint to each brick, those figures fall to roughly 68, 59, and 73 per square metre.
Should I subtract doors and windows from the wall area?
Yes. Measure the full wall as length times height, then subtract the area of every door, window, and other opening. Openings still need some cut bricks around their edges, and the waste allowance covers those cuts, but counting the whole opening as solid brickwork would over-order by far more than the allowance. For a wall with a large garage door or several windows, the deduction makes a real difference to the order.
What waste allowance should I add for bricks?
Use 5 percent for a plain rectangular wall with few cuts, and 10 percent for a typical wall with corners, openings, and piers. Allow 10 to 15 percent where there are arches, curves, soldier courses, or many short cuts, and add a further 5 percent for soft or reclaimed bricks that break more in transport and handling. Running short mid-build is worse than having a small surplus, because a second batch may not match the colour.
Do I count the mortar joint in the brick size?
You can, but only once. Either divide by the bare brick face and let the waste allowance absorb the joints, or divide by the laying module, which is the brick plus one 10 mm joint in each direction. What you must not do is both: entering the laying module and then adding a full waste allowance double-counts the joints and over-orders by roughly a fifth. Pick one method and stay with it for the whole wall.
How many bricks do I need for a double-thickness wall?
Twice as many as for a single skin of the same area, because each leaf of the wall is a separate layer of bricks. Run the calculation once per leaf and add the two counts together. A cavity wall works the same way: count the outer leaf and the inner leaf separately, then add them. Wall ties, insulation, and lintels are separate items and are not included in the brick count.
How many bricks are in a pallet or a pack?
It varies by supplier and brick type, so there is no single answer. A common UK pack holds around 400 to 500 bricks, while US pallets are often 500 to 600, but both figures change with brick size, weight limits, and the supplier. Once you know your total, divide it by the pack size your supplier actually sells and round up to whole packs. Always confirm the pack size before ordering, not after.