Brick Calculator

Bricks = ceil( area × (1 + wastage ÷ 100) ÷ ((length + joint) × (height + joint)) × leaves )

L

Length of one brick, plus one mortar joint — the module a brick occupies along the wall

H

Height of one brick, plus the joint — the module it occupies up the wall

leaves

How many bricks sit across the wall's thickness: 1 for a half brick wall, 2 for one brick, 4 for two brick

A

Face area of the wall, in square feet

w

Wastage allowance, as a percentage of the net count

Use it before you order brick, and use the wall field honestly — the same 100 square feet is 720 bricks as a half brick wall and 2,880 as a two brick wall. The count is rounded up to whole bricks and the wastage allowance is applied to the area first, so the mortar grows with it: the extra square feet you are covering for breakage need bedding too. For a block wall use the concrete block calculator instead, which has no wall field because a block wall is one block thick.

1. 100 square feet of half brick wall in modular brick, 5% allowed

   1. One brick plus its joint occupies (7.625 + 0.375) × (2.25 + 0.375) = 8 × 2.625 = 21 in² of wall
   2. 21 in² = 0.1458 ft², so one square foot holds 6.86 bricks
   3. Area with 5% allowed: 100 × 1.05 = 105 ft²
   4. Bricks: 105 × 6.857 = 720.0
   5. Wall thickness: one leaf = 3.625 in = 0.0921 m
   6. Mortar: (0.0921 − 73.81 × 0.0010193) × 9.755 m² = 0.1643 m³ = 5.81 ft³

   6.86 bricks per square foot is the figure printed in American masonry tables for modular brick, and it falls straight out of the modular arithmetic: 8 inches plus the joint is 21 square inches, and 144 ÷ 21 = 6.86. The wall is one leaf thick, so nothing is multiplied — this is the simplest case on the page and the baseline every other wall is a multiple of. The mortar is 18% of the wall's volume at one leaf.

2. 100 square feet of two brick wall in standard brick, 5% allowed

   1. One brick plus its joint: (240 + 10) × (53 + 10) = 250 × 63 = 15,750 mm² = 0.01575 m²
   2. One square metre holds 1 ÷ 0.01575 = 63.5 bricks in one leaf
   3. A two brick wall is four leaves: 63.5 × 4 = 254 bricks per m²
   4. Area with 5% allowed: 100 ft² = 9.290 m², × 1.05 = 9.755 m²
   5. Bricks: 9.755 × 253.97 = 2,477.4, rounded up to 2,478
   6. Wall thickness: 4 × 115 + 3 × 10 = 490 mm
   7. Mortar: (0.490 − 253.97 × 0.0014628) × 9.755 = 1.156 m³ = 40.82 ft³

   254 bricks per square metre is the four-leaf figure; halve it twice and you have the 127 of a one brick wall and the 63.5 of a half brick wall, which is what makes the four wall options a single number multiplied rather than four separate coefficients. The mortar is 24% of the wall's volume here against 18% for a single leaf — thicker walls need proportionally more mortar, because every leaf adds a bed joint.

3. 200 square feet of one and a half brick wall in queen brick, 10% allowed

   1. One queen brick plus its joint: (9.625 + 0.375) × (2.75 + 0.375) = 10 × 3.125 = 31.25 in²
   2. 144 ÷ 31.25 = 4.61 bricks per square foot in one leaf
   3. One and a half brick is three leaves: 4.61 × 3 = 13.82 bricks per ft²
   4. Area with 10% allowed: 200 × 1.1 = 220 ft²
   5. Bricks: 220 × 13.82 = 3,041.3, rounded up to 3,042
   6. Wall thickness: 3 × 3.125 + 2 × 0.375 = 10.125 in
   7. Mortar: (0.2572 − 148.8 × 0.0013555) × 20.44 m² = 1.134 m³ = 40.05 ft³

   The queen brick is longer and thinner than the modular, so it covers more wall per brick — 4.61 per square foot against 6.86 — but a three leaf wall of it is still only 10 inches thick. That pairing is the point of having both the brick and the wall field: the same 200 square feet is 3,042 bricks here and 4,526 in modular brick.

The brick dimensions are nominal sizes, and a real pallet is not exactly nominal: fired brick varies by a millimetre or two per unit, and the joint is yours to control on the trowel — a joint 2 mm wider than the one assumed here is about 3% more wall for the same number of bricks. The count assumes whole bricks everywhere and ignores cutting, so openings, corners, bond patterns, arches and any wall under about a square metre will need more than this returns — that is what the wastage field is for, and 5% is the floor rather than a safe figure for a wall with openings in it. The mortar comes from wall volume minus brick volume, which is exact for solid brick, but it assumes a full bed and perpend on every unit; a wall that is not filled solid, or one built with a rake-out finish, will use less. The densities and the joint widths behind the table are industry-typical figures rather than a specification: the page calculates them from the dimensions rather than quoting a standard, and no standard is being claimed.

How many bricks are in a square foot?

6.86 for a modular brick laid as a single leaf, and 4.61 for a queen brick. Both come from the brick plus one mortar joint: 8 × 2.625 inches is 21 square inches, and 144 ÷ 21 = 6.86. Multiply by how many leaves thick the wall is — a one brick wall is two leaves and so takes 13.71 per square foot.

How much mortar does a brick wall use?

For standard brick, roughly 0.022 cubic metres per square metre of half brick wall, rising to about 0.054 for a one brick wall and 0.119 for a two brick wall. That is the wall's volume minus the volume of the bricks in it, which is exact for solid brick and needs no coefficient. It comes out at about 18% of the wall's volume for a single leaf and 24% for four leaves, because each extra leaf adds another bed joint.

How much wastage should I allow for brick?

5% on a plain rectangular wall with no openings, and 10% or more once there are windows, corners, a soldier course or any cutting. Brick is cut with a bolster or a saw and the offcuts are rarely reusable, so the rule of thumb is one extra brick for every twenty when the wall is plain, and one for every ten when it is not. The field takes anything from 0 to 30.

What is the difference between a modular brick and a queen brick?

Size, and the size is chosen to fit a module rather than a look. A modular brick is 7⅝ × 3⅝ × 2¼ inches, so with a ⅜ inch joint eight of them plus joints make exactly 64 inches, and three courses make exactly 8 inches. A queen brick is 9⅝ × 3⅛ × 2¾, which fits a 10 inch module. The page uses the actual dimensions, not the nominal ones, which is why the counts come out at 6.86 and 4.61 rather than the rounded figures a masonry table prints.

How thick is a one brick wall?

Two bricks wide: 240 mm for standard brick, or 7⅝ inches for a modular brick. The names count leaves, not inches — a half brick wall is one leaf, one brick is two, one and a half brick is three and two brick is four — and the metric names for the same four walls, 12, 24, 37 and 49, are nominal thicknesses in centimetres. The page reports the wall thickness it actually used, in the table, so the two can be reconciled.

Does the count include the bricks in the corners and openings?

No. The page multiplies a face area by a rate, so it knows nothing about where the walls meet or where a window is. Corners take slightly more because of the bond, openings take less brick but a great deal of cutting, and the two do not cancel out — which is exactly why the wastage allowance is a field rather than a fixed 5%. For anything with more than a couple of openings, measure the net areas and add them up rather than measuring the whole elevation.

• Approximate Conversions from U.S. Customary Measures to Metric — the chart behind the inch, foot and square foot figures used here — National Institute of Standards and Technology
• The International System of Units (SI) brochure — the metre and its multiples, the units the brick and joint dimensions are defined in — Bureau International des Poids et Mesures (BIPM)