Brick calculator

Come up short on bricks halfway through a wall and you're waiting on a delivery, maybe from a different batch that doesn't quite match. This calculator works out how many bricks a wall needs, plus a guide to the building sand, so you can order once. Here's how it's worked out.

How to work out how many bricks you need

It's the wall area times the number of bricks per square metre, with a little wastage on top.

Bricks = wall area × bricks per m² × (1 + wastage).

A 10m by 2m wall is 20 square metres. As a single-skin wall uses about 60 bricks per square metre, that's 1,200 bricks, or about 1,260 with 5% added for cuts and breakages. The calculator does it from the wall size and the thickness you pick.

Bricks per square metre

The standard UK brick is 215 by 102.5 by 65mm, and with a 10mm mortar joint it works out at roughly 60 bricks per square metre for a single-skin wall. A double-skin wall, being twice as thick, needs about 120 per square metre.

Single skin or double skin?

A single-skin wall is one brick laid flat, 102.5mm thick, used for garden walls, low boundary walls and the inner leaf of a cavity wall. A double-skin wall is a full brick thick, 215mm, or two leaves, used where the wall is structural or needs to be more substantial. Choosing the wrong one is an easy way to order half the bricks you need, so the calculator makes it a clear toggle.

How much sand and cement?

The mortar is the other material. As a working guide, about 1 tonne of building sand lays around 1,000 bricks, mixed with cement at your usual ratio, commonly 1 part cement to 5 or 6 of sand. So a 1,260-brick wall wants a bit over a tonne of sand. It's only a guide, because joint size and how full you lay the beds both change it, so round up and treat the calculator's sand figure as a starting point.

Wastage and matching the batch

Allow around 5% wastage for the cuts at corners and openings and the odd brick that snaps. Add more for a wall with lots of openings, curves or feature work. As with any batch material, buy your bricks in one order and keep a few spare, because bricks from a later batch can differ slightly in colour.

From materials to a priced job

Bricks and mortar are the materials; the skill and the labour in the laying are the bigger part of the price. Work the whole job out with how to price a job so you actually make a profit, put the materials into a clean, itemised quote with the quote generator, and use the gravel and aggregate calculator for the sand and any foundation sub-base by the tonne.

This tool is for general estimating and gives approximate quantities. Brick sizes, joints and mortar mixes vary, so check your own measurements, and order a sensible amount over rather than exactly to the calculation.