Room Brick Calculator

How to use the room brick calculator

Each row represents one wall. Add a row for every wall in the room, including internal walls if you're building them too.

1. Enter the width and height of each wall, in metres. A rectangular room typically has four walls. Measure each one separately, since opposite walls aren't always exactly the same length in an existing structure.
2. If a wall has a door or window, enter its total opening area in the same row's 'Doors/windows' field. Two windows in one wall means adding both areas together before entering the figure. Leave it at 0 for a solid wall.
3. Click 'Add another wall' for each additional wall, up to 12 rows. Use 'Remove' on a row you no longer need.
4. Choose your brick type and wall type once, at the top. These apply to every wall in the calculation, so run the tool a second time if one wall uses a different brick or skin type than the rest.

Why room-level totals need their own calculation

Running the single-wall calculator four times and adding the results by hand works, but each of those four separate 'before waste' and 'after waste' numbers has to be tracked and summed correctly, and a waste allowance applied per wall instead of once across the room can round differently to a whole-room total. This tool sums the net wall area first (gross area minus openings, wall by wall), then applies the brick type, wall type and waste allowance once to the combined total, which matches how a quantity surveyor typically prices a full room rather than wall-by-wall.

Corners aren't subtracted separately. Measuring each wall to its own full face length and adding the four totals together is standard practice, because the bricks along a corner belong to one wall's face or the other in the bond pattern, not to both, so there's no double count to correct for.

Worked example: a 4m x 3m room

A small room, 4m by 3m, walls 2.4m high, standard brick, double-skin, one door (1.8m²) in one of the 3m walls, one window (1.5m²) in one of the 4m walls, 7% waste allowance:

• Wall 1 (4m): 4m × 2.4m = 9.6m², minus 1.5m² window = 8.1m²
• Wall 2 (4m): 4m × 2.4m = 9.6m², no opening
• Wall 3 (3m): 3m × 2.4m = 7.2m², minus 1.8m² door = 5.4m²
• Wall 4 (3m): 3m × 2.4m = 7.2m², no opening
• Net area total: 8.1 + 9.6 + 5.4 + 7.2 = 30.3m²
• Bricks per m² (standard, double-skin): 50 × 2 = 100
• Before waste: 30.3 × 100 = 3,030 bricks
• With 7% waste: 3,030 × 1.07 = 3,243 bricks, rounded up
• At 500 bricks per pallet: 7 pallets

Enter these same four walls into the calculator above to check the result, then adjust any figure to match your own room.

Common mistakes at room level

A few errors show up more often once several walls are combined into one total, rather than checked one at a time:

• Forgetting an internal wall entirely. A room isn't always four external walls, and a partition wall inside the same room needs its own row, usually single-skin even when the outer walls are double-skin.
• Entering a door or window's area on the wrong wall. The opening only reduces the wall it's actually in, not the room total generally, so a door in wall 3 has to be subtracted from wall 3's own row.
• Adding two windows in one wall as one entry with the wrong combined figure. Two 0.75m² windows in the same wall need a combined 1.5m² in that wall's opening field, not 0.75m² twice across two separate rows.
• Mixing brick types across walls without running the calculator twice. If one wall uses maxi brick and the rest use standard, calculate the maxi wall on its own with the single-wall calculator and add that figure to this tool's total for the remaining walls.

Once you have your room total

The result above already includes your waste allowance and a pallet count. For the manual formula behind the figures, see how to calculate bricks. For a full pricing picture once you have quotes, the brick wall cost calculator turns this brick count into a total material cost.