Floor screed for self-levelling or traditional sand/cement — volume, weight and 25kg bags.
Multiply floor area by screed depth to get volume. Sand/cement screed weighs about 2.1 tonnes per cubic metre, so you can convert straight to 25kg bags. Traditional sand/cement screed is laid 50–75mm deep; self-levelling compounds are thinner.
A traditional sand/cement screed is usually 50–75mm. Bonded screed can be thinner (25–40mm); floating screed over insulation is typically 65–75mm.
At 50mm depth you need about 2.6 bags per square metre. Use the calculator for your exact depth and area.
Sand/cement is cheaper for deep build-ups; self-levelling is faster and thinner for smoothing over an existing slab.