Paint Calculator UK
Work out how many litres of paint you need from the area you will actually paint, the coat count for your chosen product and its stated coverage. Nothing is hidden: extra allowance starts at 0%, and tin rounding is optional.
Calculate your paint quantity
Enter the paintable area plus the coat count and coverage for the exact paint you intend to use. If you do not know the area yet, use the Wall Area Calculator or the Room Decorating Estimator first.
How the paint calculation works
Extra allowance is applied only after the base litres have been calculated. If you enter a tin size, the final purchase quantity rounds up to whole tins.
Worked example
45 m² × 2 coats ÷ 12 m²/L = 7.50 L.
At 0% extra the planning quantity stays 7.50 L. With a 5 L tin entered, that becomes 2 tins / 10 L bought.
Why coverage and coats are editable
Paint is not one standard material. Dulux’s current UK guidance tells users to use the square-metres-per-litre figure for the chosen paint, and its own calculator notes that recommended coat counts vary between products. Current Dulux product pages demonstrate that difference: some products are one-coat while others specify two coats, and published coverage values vary between ranges.
Use actual wall or ceiling measurements and deduct significant openings if you want a net area. Keep surfaces using different paints in separate calculations.
Enter the coat count and coverage from the tin, technical/product information or manufacturer guidance for the product you intend to buy.
Choose any extra allowance yourself. If you enter a real tin size, the calculator shows the whole tins required and the nominal surplus.
Do not use floor area as wall area
A 20 m² room floor does not mean 20 m² of wall. For walls, calculate the actual wall surfaces first. The Wall Area Calculator handles that geometry; this page deliberately owns the paint quantity from a known paintable area.
Should doors and windows be deducted?
Deducting large openings gives a closer geometric wall area. For small openings, the saving can be modest and cutting-in, texture or touch-up work may offset some of it. The important point is to use one consistent paintable-area figure rather than subtracting areas twice.
What does “coverage per litre” mean?
Coverage is the area a product says it can cover per litre under stated conditions. Treat it as product-specific information, not a universal paint constant. Surface porosity, texture, colour change and application can affect real consumption, so check the exact product guidance before buying.
Paint calculator vs room decorating estimator
This calculator is the fast tool when you already know the paintable area. If you want to plan walls, ceiling and other decorating quantities from room dimensions, use the Room Decorating Estimator. For the measuring method behind this calculation, see the paint quantity guide.
Planning estimate only. This calculator does not choose the correct paint, preparation system or number of coats for your surface. Follow the current instructions for the exact product and substrate.