Floor Screed Calculator
Enter floor area and screed thickness to compute the cement-sand mortar volume, then estimate cement bags and loose sand by mix ratio for home or site levelling.
Input Data
Results
At a glance:Screed mortar volume = area × thickness(mm) ÷ 1000 × (1 + wastage%). With cement parts c and sand parts s, total parts = c + s. Total mortar weight = volume × wet density; cement weight = total weight × c ÷ (c + s); sand weight = total weight × s ÷ (c + s). Cement bags = cement weight ÷ bag weight (rounded up); loose sand volume = sand weight ÷ 1,500 kg/m³.
Formula
Volume = area × thickness/1000 × (1 + wastage%)
Total weight = volume × wet density
Cement weight = total weight × c/(c+s)
Bags = ⌈cement weight ÷ 50⌉
Sand volume = sand weight ÷ 1500
$$V = A\frac{t}{1000}(1+w)$$$$W_t = V\rho$$$$W_c = W_t\frac{c}{c+s}$$$$B = \left\lceil \frac{W_c}{50} \right\rceil$$How to Use
- Enter the floor area (m²).
- Enter the screed thickness (mm).
- Select the cement:sand ratio.
- Confirm the wet density and wastage.
- The tool outputs screed volume, cement bags and sand volume.
Case Studies
Bathroom levelling
8 m², 50 mm, 1:4, 10% wastage.
Mortar 0.44 m³; cement 3.5 bags (4 bags), sand 0.19 m³.
Whole-flat screed
40 m², 40 mm, 1:4, 10% wastage.
Mortar 1.76 m³; about 14 cement bags, 0.76 m³ sand.
FAQ
How does screed differ from a concrete slab?
The concrete slab is the structural layer; the screed is a thin cement-sand layer on top, used to level before tiling or flooring.
Why does thickness matter so much?
Mortar volume is proportional to thickness; 50 mm uses about 67% more material than 30 mm, so measure accurately.
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References
Content review: Calculatorism Construction Team. Results are for reference only; please refer to the relevant authorities for the official figures.