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Paint calculator

Metric Paint Calculator

Estimate interior wall paint from room dimensions, coats, coverage, waste, openings, container size, and optional container price.

Room length (m)Measure the longer wall, in metres.Room width (m)Measure the shorter wall, in metres.Wall height (m)Floor to ceiling height.Number of coatsUse whole coats only.Paint coverage (m2/L)Use the product label coverage.Waste percent (%)Allows for touch-ups and surface variation.Door/window opening area (m2)Optional area to subtract from the walls.Container size (litres)Containers are rounded up.Price per container (optional)Used only to multiply whole containers by your entered price.

Estimate

Enter measurements and calculate to see the paint estimate.

Formulas and assumptions

Gross wall area = 2 x (length + width) x height.
Net wall area = gross wall area - door/window opening area.
Litres before waste = net wall area x coats / coverage.
Waste is applied after the base litre calculation.
Application method, surface condition, colour change, and product coverage can change actual paint needed.

Planning estimate only. Not engineering, structural, legal, installation, or supplier advice. Check measurements, site conditions, and product labels before buying or building. This paint estimate uses the coverage and container size entered on this page.