Brick Calculator

What the brick calculator does

Order bricks short and the job stops; order long and you are stacking pallets you cannot return. This works out the count. You give it the wall size, the brick size, the mortar joint, and a waste figure, and it returns the bricks needed, the wall volume, the mortar volume, and a cost if you add a price per brick.

It counts the way a bricklayer does, by the face the wall shows. Below is how it works, and the two things, the joint and the wall thickness, that decide the number.

How to use it

1. Enter the wall length and height, each with its unit, and choose the wall thickness.
2. Enter the brick length, width, and height, the size of a single brick.
3. Enter the mortar joint you will lay between bricks, and a waste percentage.
4. Add a price per brick if you want a cost, pick the output unit, then press Calculate, or Reset to clear it.

How the brick count is worked out

The count comes from the area of the wall face divided by the area each brick takes up on that face:

Bricks = wall face area ÷ area of one brick plus its joint

The brick face the wall shows is its length by its height, the long side laid as a stretcher. Once it has the raw count, the calculator adds your waste percentage and rounds up. For a standard brick at a 3/8 inch joint this works out to about 7 bricks per square foot, or roughly 60 per square meter. That gives the count for one leaf of brick; a thicker wall multiplies it, which the thickness section covers.

Why the mortar joint is in the sum

The joint matters because a brick never sits tight against its neighbour; there is a band of mortar around it. So on the wall each brick really occupies its own size plus one joint in each direction, and the calculator builds that in by adding the joint to the brick's length and height before working out the area it covers.

That keeps the count honest, and it cuts both ways. A standard 3/8 inch joint gives the familiar 7 bricks a square foot. Lay a thinner joint and you fit more bricks; lay a fatter one and you fit fewer and use more mortar. So the joint you enter should be the one you actually intend to lay.

Wall thickness and leaves of brick

A wall can be one leaf of brick or two, and that choice changes the count, not just the volume. The thickness selector has two settings. Half Brick is a single leaf, one brick-width thick, the wall you see as a garden wall or as the brick face on a house. Single Brick is a full one-brick wall, about two leaves thick, with brick laid across the whole face twice.

The calculator reads that setting into the count. A single leaf is counted once; a one-brick wall takes roughly double the brick for the same wall face, and the tool doubles it for you, so you do not have to work out each leaf by hand. Set the thickness to match what you are building, and remember bricks are sold by the pallet, around 500, so round your order up to the next pallet.

A worked example: a 10 by 8 wall

Say the wall is 10 feet by 8 feet, a single leaf on the Half Brick setting, in standard brick with a 3/8 inch joint and 10 percent waste.

The face is 10 × 8 = 80 square feet. At about 7 bricks a square foot that is roughly 560 bricks, and adding 10 percent waste brings it to about 616 bricks. The mortar works out to a volume you can turn into bags at a rate of roughly one 80 pound bag per 30 bricks, so around 20 bags here.

Built on the Single Brick setting instead, a full one-brick wall, the same face takes about double, near 1,230 bricks, which the calculator now works out for you.

Questions people ask

How many bricks do I need?

Divide the wall face area by the area of a brick plus its joint, then add waste. For standard brick at a 3/8 inch joint that is about 7 a square foot, so an 80 square foot single-leaf wall is roughly 616 bricks with 10 percent waste.

How many bricks are in a square foot?

About 7 for a standard modular brick with a 3/8 inch joint, or close to 60 per square meter. Larger bricks cover more, so fewer per square foot.

Does a thicker wall need more bricks?

Yes. A full one-brick wall, about two leaves thick, takes roughly double the brick of a single leaf for the same wall face, since you lay brick across the face twice. Pick the Single Brick setting and the calculator counts it for you.

How much mortar will I need?

Roughly one 80 pound bag of pre-mixed mortar per 30 bricks at a standard joint. A fatter joint uses more, a thinner one less.

References

A quick note on the numbers. The bricks-per-area figures, around 7 a square foot for modular brick at a 3/8 inch joint, follow the standard face counts published by the Brick Industry Association, which already account for the mortar joint. The count itself is geometry, the wall face divided by the brick face plus its joint. The unit conversions follow the US National Institute of Standards and Technology guide.

1. Brick Industry Association (BIA), Technical Note 10 (brick sizes and quantities per area). https://www.gobrick.com
2. National Institute of Standards and Technology (NIST), Special Publication 811, Guide for the Use of the International System of Units (SI). https://www.nist.gov/pml/special-publication-811