It’s the million-dollar question: how much paint do I need for one wall? The painting of the house’s walls is one of the most accessible works to be done in DIY. Few can say that they have never ventured into their life with this activity.

But, like all works of this kind, an important starting point is to get the right amount of material. Because one of the most common mistakes is buying too much or running low. Learning to calculate the right amount of paint to buy is very crucial. One of the most common mistakes is buying too much or running low. For example, if you want to use an automotive paint gun, you will need less paint than standard roller (they use 33% more color).

To avoid this, it is essential to establish some calculations that will solve this problem. Although on the Internet there are several calculators with formulas, today, we are going to see the steps to follow.

How Much Paint Do I Need for One Wall: Step by Step?

First of all, you should know that each painting has a different performance. They are expressed in square meters per liter (m2 / l) or square meters per kilo (m2 / kg), depending on the filling unit. Some references may cover more than others due to their technical characteristics, the type of roller used, etc. In other words, the coverage you have will determine the amount of paint you will need. 

So, let’s suppose we want to paint the wall of a room: we will first have to calculate the square meters of the surface to be painted. 

To start, measure the surface to be painted, multiplying the height by the width or base to obtain the square meters of each wall or plane to be painted.

  • This a rectangular wall, for example:

2.5m height x 4m base = 10m2 of surface

  • On triangular walls or with the ceiling with a marked slope, you will measure its height in half and multiply by the base meters. For example, a 4-meter base wall with a 2-meter side and a 4-meter side:

4m base x 3m height = 12m2 of surface

After calculating the surfaces, you will need to know how much the paint to use yields. An estimated yield per liter per hand is indicated on all containers. Keep in mind that good quality paint pays more than an economic one. 

 Besides, the surface has a lot to do. On rough walls, the paint can yield half or less than what is indicated on the packaging. Remember that the application of sealant fixative or a similar material increases performance. 

Wall paints usually yield:

  • 10 m2 per liter with quality paints
  • 6 to 4 m2 per liter in rough and textured finishes
  • 5 m2 per liter with cheap paints
  • 12 m2 per liter of synthetic enamels

Once the surface is to be painted, it is calculated by adding all the partial areas of all the walls, dividing it by redeeming the paint, and multiplying it by the number of hands. For example:

(10m2 of wall/10m2 of performance per liter) x the number of hands needed

(10/10) x 2 = 2 liters of paint

Not to discount doors and windows since there should always be a bit of paint leftover. As it is still better to round up because the errors are always around the corner. Especially for non-experts, as an alternative to buying 10% more paint, you could choose not to exclude the gaps in doors and windows from the calculation surfaces.

Factors to keep in mind while calculating the amount of paint

Measure carefully

Take all the measures of the room and walls you want to paint and mark on a sheet or your smartphone. 

Remember to mark:

  • Height and width of the walls, including the ceiling;
  • Floor-length and width of the room;
  • Little noticeable corners and recesses;
  • The height between the ceiling and your arm stretched upwards       

Materials needed for painting

Material has a direct relation to the amount of paint. Not all the equipment uses the same amount of paint. Like we said at the beginning of this article, automotive paint gun uses 33% more color than others. Because, while using the sprayer, it vaporizes some of the paint into the air. But standard roller uses most of the paint on the wall. So, keep this in mind while calculating.

Some other materials needed:

  • Rolls of scotch paper
  • A spatula for walls
  • A cellophane sheet large enough to protect furniture and sofas well
  • Latex gloves
  • Finally, of course, the colors chosen for the walls.

Giving a second hand is fundamental.


The last fact to keep in mind is to remember to give the second coat. Plan your time to spend the first coat in the morning, to allow the paint to dry thoroughly. Meanwhile, you will be able to spend the second coat of color in the early afternoon. You will get an excellent result, and in one day, you will have finished painting your wall. That is why, while calculating the amount, think this through. 


Calculating how much paint do I need for one wall is not simple, especially as a beginner. But if you want to paint yourself, it is better to learn to calculate.  It’s a bummer to spend buying paint, but it is also a hassle if you haven’t bought enough, and you have to half-do what you’re doing, right? We’ve prepared this article for you to help you quickly calculate the amount of paint needed for a wall. You just have to learn the performance of the paint, the measurements of the walls, ceiling, and the elements that you are not going to paint (door, windows).