Paint calculator
Work out the litres, the tins and the cost for walls, roofs and floors.
1. Measure your walls
Tip: for a whole room, add each wall, or enter the total wall length as the width.
1. Measure your roof
1. Measure the floor
2. Choose your paint
Paint calculator questions
How do I work out how much paint I need?
Measure the width and height of each wall and multiply them to get square metres. Take off doors and windows, multiply by the number of coats, then divide by the coverage on the tin (square metres per litre). The calculator does this for you and adds a little extra for touch-ups.
How many coats of paint do I need?
Most wall paints need two coats over a prepared, primed surface. Roof paint and big colour changes can need a third coat. Each product in the calculator starts with the usual number of coats and you can change it.
Why does the calculator add extra paint?
Rough plaster, textured walls and roof tiles soak up more paint than smooth surfaces, and it helps to keep a little for touch-ups. We add 10% by default.
How do I measure a roof for paint?
Measure the length and width of the house at ground level including the overhang, multiply them, and choose the roof pitch. A steeper roof has more surface area, so the calculator scales the area up for you.