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Brick and block calculator
How many bricks or blocks you need for a wall, and the cement and building sand to lay them.
You'll need about
- Wall area
- –
- Bricks
- –
- Mortar (wet volume)
- –
- Cement (25kg bags)
- –
- Building sand
- –
Includes your wastage allowance. Quantities are approximate; check against your drawings and your merchant's product sizes before ordering.
Get the full job measuredHow the numbers are worked out
The calculator uses standard UK sizes: bricks at 215 x 102.5 x 65mm and blocks at 440 x 215mm, both with 10mm mortar joints.
| Wall type | Units per m² | Mortar per m² |
|---|---|---|
| Half-brick wall (102.5mm) | 60 bricks | 0.022 m³ |
| One-brick wall (215mm) | 120 bricks | 0.050 m³ |
| 100mm blockwork | 10 blocks | 0.009 m³ |
| 140mm blockwork | 10 blocks | 0.012 m³ |
Mortar allowances include filling the frogs on bricks. To get cement and sand, the wet mortar volume is increased by about 27% to allow for the dry materials bulking down when mixed, then split by the mix ratio. Cement is taken at 1,440 kg/m³ and building sand at 1.6 tonnes/m³.
Things the calculator doesn't cover
- Cavity walls: work out each leaf separately (for example, a half-brick outer leaf and a 100mm block inner leaf), then add wall ties at about 2.5 per m² and cavity insulation.
- Piers, returns and fair-faced work, which use more bricks and more cutting.
- Lintels, DPC, cavity closers and weep vents.
- Plasticiser and any lime in the mix.
Need the whole job measured?
Send us your drawings and we take off every item, price it at current UK rates and send back an itemised estimate. From £120, in 3–5 working days.