Floor Screed Quantity Calculator
Calculate placed screed volume from floor area and average thickness, then convert that volume into a planning material quantity using an explicit density or yield assumption.
Screed inputs
Screed requirement
The floor screed quantity formula
The volume of a uniform screed layer is straightforward: floor area multiplied by thickness. The important estimating decision is which thickness represents the actual average installed layer.
Material mass = placed volume × density
Planning mass = material mass × (1 + allowance)
Why average thickness matters
If one part of the floor is 40 mm thick and another is 60 mm, using only 40 mm understates the material quantity. A measured or designed average thickness provides a more useful takeoff basis.
Worked example
For 80 m² at 50 mm average thickness, placed volume is 4.0 m³. At an assumed 2,100 kg/m³, the theoretical mass is 8,400 kg. With 7% planning allowance, the estimate becomes 8,988 kg.
Wet volume versus dry ingredients
A placed volume of screed should not automatically be converted into equal volumes of sand and binder. Mixing water, packing, compaction and shrinkage make dry-ingredient volume a different quantity. Use an approved mix design or manufacturer's yield for detailed material procurement.
Premixed screed comparison
If a premix product supplies a manufacturer-stated yield in litres per bag, the placed volume can be divided by that yield to estimate bags. That result should remain tied to the specific product documentation rather than a generic density assumption.
Common screed takeoff errors
Using minimum instead of average thickness, ignoring level variation, treating dry-material volume as placed volume, and using an unverified density can all create under- or over-ordering.
Frequently Asked Questions
Does floor area multiply by thickness?
Yes, for placed volume.
Should I use minimum or average thickness?
Use the relevant average installed/design thickness for material estimating.
Does this prescribe screed thickness?
No.
Can I calculate premix bags?
Yes, when a product yield per bag is known.