Block calculator
Work out how many concrete or breeze blocks you need for a wall, and the mortar to lay them.
Uses only the sizes you enter.
Result
You need 119 blocks for 12 square metres.
blocks
| Blocks in a square metre | 9.877 blocks |
|---|---|
| Mortar | 0.07881 m³ |
Show the workings
| Step | Sum | Answer |
|---|---|---|
| Space each block takes, with its joint | 0.45 m × 0.225 m | 0.101 m² |
| Blocks in a square metre | 1 ÷ 0.1013 | 9.877 blocks |
| Blocks for the area | 12 m² × 9.877 | 118.519 blocks |
| Rounded up | 118.519 | 119 blocks |
| Mortar to fill the joints | 1.2 m³ of wall − 1.121 m³ of bricks | 0.079 m³ |
Where the figures come from
This sum uses only the numbers you entered.
How many blocks in a square metre?
Add the joint to the block's length and height, multiply, and divide into one square metre. For a block 440 mm by 215 mm with 10 mm joints: 1 ÷ (0.45 × 0.225) = 9.877 blocks in a square metre.
Blocks come in different sizes and thicknesses, so use the size on the supplier's page.