Floor Screed Calculator

Estimate screed volume and the mass of material needed for a floor, based on area, layer thickness and density.

Formula and method

Volume is floor area multiplied by thickness. Multiplying the volume by the mixed density gives the mass of material required, before the waste allowance is added.

How to measure the inputs

Measure the floor at its longest and widest points.
Confirm the design thickness in millimetres and enter it in your chosen unit.
Take density from the product datasheet rather than assuming a value.

Worked example

Room length 13.12 ft; Room width 16.4 ft; Thickness 1.97 in; Density (optional) 992.08 lb; Waste 10 % → Screed mass: 1,091.29 lb

Practical tips

Order sand, cement or ready-mixed screed slightly ahead of the pour day.
Keep a record of the batch mix so the next floor matches.
Allow the screed to cure before laying a finished floor on top.

Assumptions

The screed layer has a uniform thickness across the floor.
Density defaults to a typical cement screed value and can be overridden.
Reinforcement mesh, fibres and curing time are not part of the estimate.

Frequently asked questions

What density should I use?

Around 1800–2000 kg/m³ for cement-based screed and 1200–1400 kg/m³ for lightweight screed. Check the datasheet of the product you will use.

How thick should a screed be?

That is a construction decision. Bonded screeds are often 25–40 mm, unbonded screeds 50 mm or more; follow the design for your floor build-up.

Does the calculator allow for shrinkage?

Only through the waste percentage. Add 5–10 % to cover shrinkage, levelling and site losses.

Related calculators

Estimate only

Results are material quantity estimates only. They are not structural design, and they are not a substitute for local building codes, engineer approval or manufacturer instructions.

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Flooring