Subfloor prep

Levelling Compound Calculator

Self-levelling compound is sold by the kilogram, but you plan a floor by the square metre. This calculator turns your area and the average layer thickness into the exact kilograms — and the number of bags — of levelling compound to order. It prepares the subfloor; the flooring that goes on top is a separate job.

Calculate the quantity →

How much levelling compound do you need?

Enter your floor area, the average layer thickness and — if it differs — the consumption rate printed on the bag. The result is the total weight and the number of bags, rounded up.

Floor area

m²

Average layer thickness

Consumption (per mm)

kg/m² per mm

Bag size

Safety margin

You need

Enter a floor area and a layer thickness to see the quantity.

Quantity = area × thickness × consumption rate.

Getting the layer thickness right

Find the low point and the high point of the subfloor with a straightedge and a spirit level; the difference is your maximum thickness.
Use the average depth across the room, not the deepest spot — that is what the whole area consumes on average.
Stay within the product's stated range (often 1–10 mm for a thin skim, more for a deeper compound); below the minimum it will not flow, above the maximum it can crack.

Consumption, primer and drying

The consumption rate is the one number that changes the result the most, so take it from the bag rather than a rule of thumb:

Most cementitious self-levelling compounds use about 1.5–1.7 kg per m² per mm of thickness; 1.6 is a safe default and editable above.
Prime the subfloor first: primer stops the compound drying too fast and binding poorly — it changes adhesion, not the quantity.
Add a small safety margin for an uneven subfloor or waste in mixing; the field above lets you add a percentage on top.

What this calculator does — and does not

It does

Work out the kilograms and bags of levelling compound for the subfloor, from your area, average thickness and the consumption rate on the bag.

It does not

Plan or apply the flooring that goes on top. Autolay's planner and robot handle the tiles, planks or laminate and their material list and waste — not the levelling compound, and not the pouring of it. Subfloor prep stays a manual, separate step.

Planning the floor on top

Once the subfloor is level, the free Autolay planner works out the tiles, planks or laminate for it — the material list and waste — from a photo of your floor plan, a BIM/IFC file or a 3D scan.

Open the free planner →

Levelling Compound Calculator

Calculate the quantity →

How much levelling compound do you need?

Enter your floor area, the average layer thickness and — if it differs — the consumption rate printed on the bag. The result is the total weight and the number of bags, rounded up.

Floor area

m²

Average layer thickness

Consumption (per mm)

kg/m² per mm

Bag size

Safety margin

You need

Enter a floor area and a layer thickness to see the quantity.

Quantity = area × thickness × consumption rate.

Getting the layer thickness right

Find the low point and the high point of the subfloor with a straightedge and a spirit level; the difference is your maximum thickness.
Use the average depth across the room, not the deepest spot — that is what the whole area consumes on average.
Stay within the product's stated range (often 1–10 mm for a thin skim, more for a deeper compound); below the minimum it will not flow, above the maximum it can crack.

Consumption, primer and drying

The consumption rate is the one number that changes the result the most, so take it from the bag rather than a rule of thumb:

Most cementitious self-levelling compounds use about 1.5–1.7 kg per m² per mm of thickness; 1.6 is a safe default and editable above.

Prime the subfloor first: primer stops the compound drying too fast and binding poorly — it changes adhesion, not the quantity.

Add a small safety margin for an uneven subfloor or waste in mixing; the field above lets you add a percentage on top.

What this calculator does — and does not

It does

Work out the kilograms and bags of levelling compound for the subfloor, from your area, average thickness and the consumption rate on the bag.

Levelling Compound Calculator

How much levelling compound do you need?

You need

Getting the layer thickness right

Consumption, primer and drying

What this calculator does — and does not

It does

It does not

Planning the floor on top

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Levelling Compound Calculator

How much levelling compound do you need?

You need

Getting the layer thickness right

Consumption, primer and drying

What this calculator does — and does not

It does

It does not

Planning the floor on top