Materials
Finish / adhesive coverage
- where
- litres required (L)
- area (m²)
- coats
- coverage (m²/L)
- order quantity (L)
- waste (%)
Explain this equation
Works out how many litres of paint, oil, varnish or liquid adhesive you need for an area and number of coats.
A is the area in m². n is the number of coats. c is the coverage of the product: how many square metres one litre covers in one coat. V is the net litres, w the waste percentage and Vo the order quantity.
Each coat covers the whole area again, so the total area to treat is A × n. Dividing by coverage gives litres. (1 + w/100) adds an allowance for loss in tins, trays and brushes.
20 m² in two coats at 10 m²/L needs 4 L, or 4.4 L with 10% waste. Rough or absorbent surfaces lower c and raise the quantity.
Watch out: products sold by kg per m² need a different conversion.
Calculate product quantity from area, coat count and declared coverage.
Enter your values to see the result.
Good to know
Coverage is per litre per coat. Use the specific product, substrate and application method; adhesives stated in kg/m² need a different unit conversion.
Limits
Flooring gaps, slide clearances, fire-door gaps, fixing schedules and finishes must follow the design and product instructions.
Sources
- Geometry / arithmetic
This is a calculation aid, not a structural design or compliance certificate. Every default is an example, not a specification for your project.