Use our screed calculator to estimate the volume and cost of floor screed for your project. Supports metric & imperial units, plus multi-currency pricing.
Enter your measurements above to see the results.
The wet screed volume is length × width × depth, plus your waste allowance (imperial entries are converted to metres first). A dry-volume factor of 1.3 accounts for compaction. For a site mix, the dry volume is split by the chosen sand:cement ratio — cement is converted to 25 kg bags at 1440 kg/m³ and sharp sand to tonnes at 1.6 t/m³. As an alternative, the pre-mixed estimate assumes roughly 85 × 25 kg bags per cubic metre. Total cost is the volume multiplied by your cost per unit.
A 5 m × 4 m floor at 50 mm depth = 1.0 m³ of screed. At a 1:4 mix that is about 15 × 25 kg cement bags and roughly 1.66 tonnes of sharp sand, or about 85 × 25 kg pre-mixed screed bags.
Standard floor screed is a 1:4 mix of cement to sharp sand. Stronger screeds use 1:3. This calculator supports 1:3, 1:4 and 1:5.
Typical thickness is 50–75 mm. The minimum is around 40 mm for bonded screed, 50 mm unbonded, and 65–75 mm floating over insulation.
Multiply length × width × thickness for the volume, then this calculator splits it into cement bags and sand, or gives an equivalent pre-mixed bag count.
It is a close estimate based on standard densities and a 1.3 dry-volume factor. Add a small waste allowance for spillage and uneven substrates.
Site mixing (cement + sharp sand) is cheaper for larger areas; pre-mixed bags are convenient for small jobs. The calculator gives both so you can compare.
