Decorating & interiors
Paint Calculator
Wall area minus openings, times coats, divided by coverage - the arithmetic that stops the second trip to the shop.
Calculator
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How it works
Wall area = 2 x (length + width) x height, minus about 1.9 m2 per door and 1.4 m2 per window. Standard emulsion covers around 12 m2 per litre per coat; two coats is the norm on colour changes.
Frequently asked questions
How much paint for a 4 x 3 m room?
With 2.4 m ceilings, one door and one window: about 30 m2 of wall. Two coats at 12 m2/L is 5 litres - one 5 L tin with a little spare.
Does one-coat paint really work?
On a similar colour, often. Over a strong colour change or fresh plaster, plan two coats regardless of the label - and prime bare plaster first.