How do I calculate floor screed quantity?

Multiply floor area by screed thickness to get volume, then convert that volume to cement, sharp sand or ready-mix mass and round bags up.

What mix ratio should I use for floor screed?

A 1:4 cement-to-sharp-sand style screed is a common domestic starting point, while heavier-duty work may use a stronger mix. Always check the specification.

How much waste should I add?

A 5-15% allowance is common for uneven substrate, mixing loss and bag rounding. Complex floors may need more.

Is this the same as a self-leveling compound calculator?

No. This page estimates traditional floor screed materials. Self-leveling underlayment has product-specific coverage and thickness limits.

Floor Screed Calculator

Estimate floor screed volume, cement, sharp sand, ready-mix weight, waste allowance and bag counts from area and thickness.

Floor size

Length (m)

Width (m)

Thickness (cm)

Screed mix

Bag weight (kg)

Waste allowance (%)

Estimate screed materials

English floor-screed search intent is practical material estimating: floor area, screed thickness, mix ratio, waste allowance and a shopping-list style split between cement, sharp sand or ready-mix bags.

Enter the floor area directly or calculate it from length and width.
Set the screed thickness in centimeters.
Choose a 1:3 or 1:4 sand-cement mix, or use ready-mix screed.
Add a waste allowance for uneven substrate, handling loss and bag rounding.

V = S \cdot h

V — screed volume, S — floor area, h — screed thickness converted to meters.

M_{w a s t e} = M \cdot (1 + \frac{r}{100})

Mwaste — material mass with waste, M — base material mass, r — waste percentage.

B a g s = ⌈ \frac{M _{w a s t e}}{M _{ba g}} ⌉

Bags — whole bags to buy, Mwaste — material mass with waste, Mbag — one bag weight.

Thickness and use cases

Use case	Typical thickness	Planning note
Bonded sand-cement screed	25-40 mm	Substrate preparation and bonding are critical.
Unbonded screed	50 mm or more	Often placed over a membrane or separating layer.
Floating screed	65-75 mm or more	Thickness depends on insulation, loading and system design.
Underfloor heating	system-specific	Check pipe cover and the heating system specification.

Planning estimate

The calculator uses density-based estimates and does not replace the product data sheet, structural load check, substrate inspection or underfloor-heating specification.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: June 2, 2026

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