How Much Paint Do You Need?

Estimate paint from the area you will actually coat, the manufacturer’s coverage, the number of coats and an allowance. Measure walls and ceilings, subtract openings that will remain unpainted, then enter the product’s own coverage in the Paint Calculator.

The information you need

• The area of each wall and ceiling, or the dimensions of simple rectangular sections.
• Windows, doors and other areas that will not receive paint.
• Coverage for the specific paint in m²/l or the unit printed by the manufacturer.
• The number of coats and an allowance for absorption, application losses and future touch-ups.

Use the coverage on the container

A product may state coverage per coat, a range or a value for a particular substrate. Keep the manufacturer’s units and do not reuse a rate from another paint. Rough, porous or uneven surfaces need a separate estimate and a test area.

Openings and complicated surfaces

Subtract an opening only when it will not be painted. Add reveals, niche sides, exposed pipes or radiators if they are part of the finish. On small areas, leftover paint for later repairs can matter more than trying to optimise a percentage.

Check the result before ordering

• Compare the calculated area with the room sketch.
• Make sure the coat count has not been applied twice.
• Round up to available container sizes and record the batch information.
• For a strong colour change, test the coverage on a small area first.

Why the estimate is still an estimate

Actual coverage changes with the tool, technique, absorption, colour and substrate condition. The calculator supports purchasing decisions, but the product data sheet and a test area remain the primary references.