How many liters of paint do I need to paint an environment?

One of the most common questions concerns the amount of paint needed to paint a particular room in the house. Let's go, step by step, on what you should do, to get the exact result of the amount of paint you need for your project.

It is important to mention that, although the mathematical formula to conclude the amount of paint to be used in the painting is exact, there may be some type of variation due to the type of surface to be painted, number of coats, as well as the type of finish. adopted. For example, the surface to be painted can vary between: plasterboard, ceiling, floor, metal, wall and wood. Here we will focus on painting walls.

The first step, before buying the paint, is to measure the place that will be painted. Proceed as follows:

  • Measure the height and length of each wall;
  • Then add the areas of the walls that will be painted;
  • If it is the case of painting windows and doors, make the calculation separately, as the type of paint used in these areas is different.

Assume that the environment to be painted has the following size:
Height = 3m (three meters)
Length = 2.7m (two meters and seventy centimeters)
Formula = Height X Length
3m x 2.7m = 8.1m2

So we have: 8.1 square meters of area

Then follow the following steps:

1- Observe the instructions on the paint can and always calculate the area to be painted.
2- Don't forget to discount gaps, windows, doors, baseboards.
3- Then apply the following formula, called “coverage rate”:

Q = Quantity of product
A = Painting area in m²
D = Number of coats recommended by the manufacturer
RP = Yield of the product (in m²) for each coat of paint.

You may never have noticed it, however, as a general rule, this formula appears on the paint can itself according to the manufacturer.


To cover an area of ​​75m² with 2 coats of paint whose average yield is 25m²/litre/coat, you will need 6 liters of paint.

75 x 2 (two coats) = 150m2

150/ 25 (each can) = 6 liters of paint