Download the GreenPainters Paint Estimating Calculator to calculate how much paint you need You can reduce the amount of paint you buy by accurately estimating the amount of paint you will need, avoiding wastage.
Calculate the surface area by measuring the length multiplying it by the height or width. Eg. A ceiling 10 meters X 4 meters = 40m2 Subtract 1-2 square meters for each window or door. Multiply this by the number of coats needed. Allow for any primer coats, or undercoats needed. Eg. 40m2 X 3 coats = 120m2 Divide this by the coverage rate for the paint. Eg. 12m2/L 120m2 / 12 = 10 litres This is the total number of litres needed for this surface. Allow 1.5 litres for three coats on a standard door
Tip: Always buy a sample pot to make sure you are happy with the colour before purchasing the amount you need. Check the sample colour in various lighting conditions on the surface you want to paint | 
