Measure the ceiling area
For a regular rectangular room, calculate length × width. For a sloped or irregular ceiling, measure the actual painted surfaces rather than relying on the floor area.
Allow for the number of coats
Multiply the ceiling area by the coats you plan to apply. Divide by the paint’s labelled coverage and add a small allowance. Some ceiling paints cover differently from standard wall paint.
Use the calculator for a full room
On the homepage, tick “Include the ceiling” to add the ceiling to the wall estimate. If you are painting only the ceiling, use the dedicated formula and example below.
Example: a 4 m × 3 m ceiling
Ceiling area = 12 m². At 10 m²/L and two coats, the theoretical amount is 2.4 litres. Including a 10% allowance gives approximately 2.7 litres.
Frequently asked questions
Is ceiling paint different from wall paint?
Often yes. Ceiling products may have different finishes and coverage rates, so check the label.
Should I use the same number of coats?
Not necessarily. Follow the manufacturer’s instructions and consider the existing surface and colour.
These calculations are estimates. Always follow the product’s coverage, preparation and application instructions.