Brick Calculator

This brick calculator allows you to calculate the number of bricks required for a wall area, amount of cement and sand for mortar and also approximate cost of entire material. It is also possible to do calculations in reverse direction. If you enter the number of available bricks, then the tool will calculate what area of wall can be built with those bricks.

It's all based on a single concept: in a wall, bricks take up not only their own dimensions but also the thickness of a mortar joint at the top and a mortar joint at the sides. This slightly larger rectangle is the unit with which the surface area of the wall is filled.

How many bricks are needed?

Subtract the area of doors and windows from the total wall surface area, then divide that result by the area taken up by a single brick together with its mortar joint. Finally multiply by the number of layers of bricks in the wall.

Here A_net is the net wall area (without openings), l and h are the length and height of a brick respectively, t is the thickness of the mortar and n is the number of layers of bricks. 1 stands for half a brick wall, 2 for a full brick wall, etc.

The length of a standard brick in the US is 194 mm, and its height is 57 mm. If the thickness of the mortar is 10 mm, then the area occupied by each individual brick will be 204 x 67 mm, or 0.013668 square meters. Therefore, for a half-brick wall, approximately 73 bricks per square meter, or 6.8 bricks per square foot, are required.

A complete example.

We are to build a partition wall with length of 4 meters and height of 2.5 meters from traditional Indian bricks with dimensions of 230x110x75 mm, mortar joints should be 10 mm, and there will be standard door with dimensions of 0.9 x 2.1 meters.

To round up the calculations and to factor in a five percent loss due to damage and breakage you need 418 bricks. This is equivalent to 49 per square meter which is exactly what most Indian builders have to keep in mind when it comes to this type of brick.

It all depends on the thickness of the walls.

A half-brick wall is a single layer of bricks laid lengthways with the thickness of the wall being the width of one brick. It's suitable for interior walls, garden walls and cladding but doesn't carry any structural loads.

A brick wall is made up of two layers of bricks doubling the thickness and also doubling the number of bricks required. For each additional half-brick layer the number of brick courses increases by one, adding a corresponding amount of extra bricks. This is an especially costly mistake to make when calculating the quantity of bricks as it can result in either doubling or halving the entire order.

Standard dimensions for bricks worldwide

Brick dimensions vary by region so incorrect assumptions here can lead to differences in the number of bricks required by a fifth or more. The standard dimensions used in this calculator are listed below as length x width x height.

All of these area calculations are based on a 10 mm mortar joint thickness. If masons use a 3/8 inch (9.5 mm) mortar joint, the number of bricks required will increase by less than one percent. Dimensions not listed can be entered in the "Custom" field. Units are either millimeters or inches.

How much mortar, cement and sand is required?

Mortar is the space between bricks in a wall. When you calculate the volume of masonry and subtract from it the volume of the bricks themselves, the remaining volume is wet mortar.

Since adding water to dry cement and sand results in a reduction of volume, more dry material is required than the calculated volume of wet mortar. Normally a factor of about 1.33 is used but some contractors use up to a factor of 1.54. The volumes of the dry materials are divided according to the mixing ratio with the amount of cement per cubic meter being quoted at 1440 kg and converted into number of bags.

The mix ratio of 1:5 means that for a volume of cement five volumes of sand are added, so r = 5. For comparison, using standard bricks measuring 230 mm in a mixture of 1:5 to build half a brick wall would require about 111 kg of cement (two or three 50 kg bags) and 0.38 cubic metres of sand.

An important point to note when comparing values is that this calculator uses the actual wall thickness so for a single skin wall mortar will be about 15% of the volume. The commonly quoted rate is between 20 and 23%. This is because nominal joints running in the direction of the wall thickness are also taken into account. These joints only exist if the wall thickness is at least two bricks though. If you prefer to err on the side of caution, then feel free to adjust the dry material volume factor yourself.

Trimming: How much more should you buy?

No one can lay all the purchased bricks into a wall without loss. Some have damaged corners already on arrival, others break during cutting. In addition, you need cut-to-size bricks for the corners and sides of openings.

For a straight wall, five percent waste is reasonable. If there are multiple doors or windows and you want to avoid cutting, seven to ten percent is appropriate. For curved or decorative layouts, or if this is your first time working with it, plan for ten to fifteen percent. Diagonal patterns like herringbone often result in more waste and can account for as much as ten to fifteen percent alone.

Order all the bricks from the same production run and have them delivered together. The color of the clay varies from batch to batch so small areas of wall made with later batches can stand out over the life of the whole wall.

Layout patterns and costs

The arrangement patterns refer to the way in which bricks are laid. Although with a given wall thickness the number of bricks that can be laid per square meter does not change, the number of cuts required varies, which affects wastage.

The running bond is the most common method of laying bricks with all facing ends laid in line. This minimizes waste. The English and Flemish bonds alternate long sides and short sides, look better and are significantly stronger but increase the cut to several percent. The herringbone pattern lays bricks perpendicular at the edges of voids reducing the number of bricks required by a fifth and improving thermal insulation. The basket weave is purely decorative with all joints running in straight lines and should never be used for load-bearing walls.

Common mistakes to avoid:

The most common mistake is to ignore the mortar joints. If you do not take into account the dimensions of bricks and mortar joints but only use the dimensions of bare bricks, for small walls you will order about ten percent more material.

Another common error is to confuse the length, width and height of a brick. The width determines the depth of the masonry and therefore the thickness of half-brick walls. If length and width are swapped, both the amount of bricks required and the wall thickness will change at the same time.

If you measure the height of your wall from the top of the foundation instead of from ground level, then the actual number of blocks required will increase without notice. If the terrain is flat, measure the height from the highest point to prevent the opposite side of the wall from being shorter than desired.

This calculator is for planning and educational purposes only. The actual amount required may vary due to tolerances in the bricks, thickness of mortar, pattern type and local conditions. Therefore, results should be considered as an estimate which will be reasonably accurate. Check with a mason and confirm with supplier before ordering.