About this calculator
Already know how many bricks or blocks you are laying? This works out the cement and sand directly.
How it’s calculated
Mortar volume per unit uses practical rates: about 0.55 m³ per 1,000 bricks and about 0.0012 m³ per 100 mm block. The wet volume is multiplied by 1.3 for dry materials, then split by the mix ratio. Cement is taken at 1,440 kg/m³ and sand at 1.6 t/m³.
Worked example
With these inputs:
- Laying
- Bricks
- Number of units
- 1000
- Mortar mix (cement:sand)
- 1:5 (general)
- Waste allowance
- 10%
the result is:
- Mortar for 1,000 bricks
- 8 × 25 kg cement + 1.05 t building sand
- Mortar volume (wet)
- 0.61 m³
- Mix 1:5 needs
- 8 × 25 kg cement + 1.05 t building sand
Tips from the trade
- Make only as much mortar as you can use in about 2 hours.
- Plasticiser makes the mix easier to work at 1:6, but don’t overdose it.
- Below the damp-proof course and in exposed walls, use a stronger mix.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and the Building Regulations before ordering.