Paint Calculator
Litres of paint for walls by area and coats.
Tip: Usually 2 coats are needed. Dark colours may need 3 coats over light walls.
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About this digital tool
The paint calculator shows how many litres of paint you need to paint a room, starting from its dimensions, the areas of the doors and windows and the number of coats. Enter the width, length and height, the deduction for openings in m² and choose 1, 2 or 3 coats.
The wall area is calculated as 2 × (width + length) × height, minus the openings, and the ceiling (width × length) is added. The tool assumes 1 litre covers about 10 m² per coat, so the litres come out as total area × coats ÷ 10. The result also shows how many 15 L or 5 L tins are needed. It suits quick painting jobs at home and decorators who want to make an accurate estimate.
How to use
- Enter the width, length and height of the room in metres.
- Enter the area of doors and windows in m² to deduct from the walls.
- Choose the number of coats: 1, 2 or 3.
- Read the litres of paint and the number of 15 L or 5 L tins.
Frequently asked questions
How much area does 1 litre of paint cover?
Most paints cover 10–12 m² per litre, per coat. With 2 coats: ~5–6 m²/litre effective.
How many litres of paint do I need for a room?
It depends on the dimensions and coats. For a 4 × 5 m room with a height of 2.7 m, no openings, two coats and the ceiling, the tool gives about 13.7 litres. Enter your room's dimensions for the exact amount.
Is the ceiling also counted in the amount of paint?
Yes, the tool adds the ceiling (width × length) to the wall area. If you paint the ceiling a different colour, calculate it separately by comparing the wall and ceiling area rows the tool shows.
How many coats of paint should I apply?
Usually two coats give even coverage. Dark colours over light walls or walls without a primer may need three coats, so choose it in the coats field.