paint calculation formula

How much paint do you need for one wall?

Paint Calculation Formula- for painting wall

How much paint do you need for a wall – The paint calculation formula lets you know how much paint to buy so you don’t have to waste time and money.

paint calculation formula

How much paint does it take to paint the walls?

One of the components of a competent repair is saving time, finances and resources. We decided to paint the walls – plan everything in advance buy a best paint sprayer for walls and calculate how much paint you will need. We will tell you how to do everything as accurately as possible – taking into account all the necessary factors and preparatory work.

What is planning and calculation for?

Even if you are far from the exact sciences, having conceived paintwork, you will have to be prudent and scrupulous. Incorrectly calculating the right amount of material, you will face a number of problems.

You will have to go to the store and buy more paint – the same color and manufacturer. It will be unpleasant if the right material is not in the store.

You may even have to repaint the surface in a different color, and this is an additional cost. If you play it safe and buy more material than you need, it’s also not good – you will exceed the budget in vain.

Why count and what to consider

paint calculation formula

Such a question can be asked by those who have already managed to go to the store, figured out what and how much they want to buy for repairs, and saw that the paint cans already indicate the consumption for painting one square meter.

It would seem that it remains only to find out the exact surface area that you are going to paint, and the calculations will be completed. Unfortunately, this is not the case.

Firstly, averaged indicators are given on the packaging, and secondly, accurate calculations based on these data cannot be made, a number of other factors must be taken into account.

In order to calculate the paint consumption per 1 m2 with minimal errors, you need to answer the following questions:

  • what tools will you use;
  • what is the original color of the painted surface;
  • how smooth is the surface that needs painting;
  • what is the type and color of the selected paint.


electric paint sprayer for walls

Paint consumption largely depends on the tools. As a rule, when painting walls are used:

  • Rollers: the average length of the pile is used to create a simple relief, a short pile is suitable, for example, for the effect of a stone wall;
  • Spray gun: suitable for all kinds of experiments and the embodiment of design ideas;
  • Wide brush: the need for it arises when creating various kinds of textures, for example, to create an aging effect;
  • Sponges, trowels.

The most economical in terms of paint consumption from the above list is a spray gun. This tool once became a real breakthrough in the construction world. The spray gun, or spray gun, is able to distribute the paint in a thin uniform layer, which significantly reduces material consumption.

Compared with a conventional brush and roller, two or even three times less paint material is used with its application. In addition, the coloring process itself takes much less time.

The most wasteful method is applying paint with a brush: different thickness of layers, streaks, and unevenness. These factors increase the expense.

Many consider paint rollers to be the best option: they are affordable and inexpensive, easy to clean, and the paint is relatively economically consumed and lies flat.

The original color and texture of the surface

paint calculation formula

The initial color of the treated walls is of great importance. For example, if you want to refresh a wall that is painted white, then one light layer will be enough. But if the new color is dark, then you will have to paint twice.

Next, it is important to know what the “hiding power of paint” is. In short, this is the ability of the material to overlap the color of the base with uniform single-layer application.

Concealment is the ability of a pigment or pigmented paint and varnish material, when applied evenly to a surface, to make the color of the latter invisible or, in the case of application to a black-and-white surface, to reduce the contrast between black and white areas of the surface until the difference in brightness between them completely disappears.

The greater the hiding power, the better the new paint overlaps the color of the old one, respectively, the better the hiding power, the more economical the use.

Summary: the smoother the walls, the less paint is consumed.

Taking into account this fact, in order to reduce the consumption of paint, the walls must be prepared for painting – leveled, cleaned to the required smoothness, carefully primed.

ATTENTION! If the surface has areas treated with plaster, the calculations should take into account the high absorbency of cement, respectively, more paint will be required.

Also as a useful reminder – the following table.

What area can be painted over with 1 liter of paint, depending on the type of surface:

  Metal         14-16 m2
  16 m2
  Polished wood     16 m2
  Embossed wallpaper   10 m2
  Freshly sawn wood   8-10 m2
  Primed plaster   15-17 m2

Paint color

paint calculation formula

The number of layers and the quality of the coating depends on the color of the paint. Since the color density depends on pigmentation, the costs will vary depending on the tone.

ATTENTION! The standard material consumption for painting in one layer is 130-140 g per 1m2. Paints of light colors have a lower density, which increases their consumption, that is, the surface will have to be painted in two or three layers.

As a rule, 1 kg of paint is enough to paint the following surface:

In white  8-10 m2
In black    18-20 m2
In blue or dark blue  15-17 m2
In green  12-13 m2
In yellow or red  8-10 m2
In brown   
 13-16 m2

Paint type

paint calculation formula

The types of paints differ from each other in their structure, respectively, different amounts of material are used to color one square meter of area.

Which paint is better to choose – acrylic, enamel, etc. – is a separate topic. In short, the composition of the surface that you need to cover with paint matters. For example, for the ceiling, as a rule, they take acrylic paint. In the case of metalwork or wood, it is better to use enamel products.

What is important for us now is the fact that the consumption of paint will differ, depending on its type. For clarity – a small table.

Acrylic 0.25   0.15
Silicone 0.30 0.15
Silicate 0.40 0.35
Polyvinyl acetate 0.55 0.35
0.60 0.40

How to do paint calculation formula

paint calculation formula

To make calculations, you need to find out 2 values:

  • the area of the painted surface;
  • standard consumption for a certain type of paint.

Let’s clearly show how to do this.

How to find out the total surface area for painting

We will need: a pencil, a tape measure, knowledge of the multiplication table, a sheet of paper.


Use a tape measure to measure the length (a) and width (b) of the walls in the room, write down the data in meters and calculate the perimeter using the formula:

P = (a+b)*2

Example: The length of one wall is 4 meters, the width is 3 meters. The perimeter will be: P = (3+4)*2 = 14 m.


Now measure the height (c) of the wall in the room (or the height of the level to which the walls will be painted). Write down the resulting figure and calculate the area using the formula:

S = P*s

Example: The height of the wall is 2.5 m, and we already know the perimeter (14 m). The area will be: S = 2.5*14 = 35 m2.

The surface area that we will paint is known. But door and window openings are not taken into account: they need to be subtracted from the resulting area.


According to the already known algorithm (see Step 1 and Step 2), we will measure the length, width and height of all available door and window openings with a tape measure and calculate their perimeter, and then the area.


From the total area of the room obtained in Step 2, we subtract the area of door and window openings calculated in Step 3.

How to calculate the right amount of paint

So, we know the area. To calculate the paint consumption, you need to divide the area by the standard consumption. As a result, we will get a figure of the amount of paint that will need to be applied in one layer.

Remember that different types of paint differ in their basic composition. Each of these varieties has its own approximate consumption per unit area (when applied in one layer).

Where to view the standard expense:

  • on a can of paint (average values);
  • according to the tables given above in this article (taking into account the color, type of paint and type of surface).

Example: Find out how much paint will be required to treat a surface area of 35m2. Let’s say, minus the area of door and window openings, it turned out to be 28 m2 – we take this figure. We look at the jar with the selected paint or tables: we are looking for material consumption per 1 m2. For example, for this case – 120 g /m2. The paint consumption is calculated by the formula

S*consumption per 1 m2 = paint consumption per room

We consider: 28 *120 = 3 kg 360 g.

This is an indicator under the condition of painting in one layer.

If the surface needs to be covered in two layers, respectively, the consumption will double.

An example of calculating the paint consumption:

Calculation of paint consumption when painting one wall of an ordinary room. Calculate the total area of the room, then subtract the area of window and door openings.

Wall height – 3 m, width – 4 m. The area will be 12 m2. Next, we calculate the area of the door opening on this wall. We get 2 m2. From the total area (12 m2) we subtract the door area (2 m2). The surface area for painting is 10 m2. Next, we will find out the required amount of paint. For example, a 2.5 l can of paint will be enough for painting in one layer of an area of 25 m2. Total: for a wall of 10 m2 for painting in 2 layers, you will need 1 can of 2.5 l paint.

We calculate the errors

Hiding power and dry residue

These indicators are usually indicated on branded products.

Dry residue – those substances that will remain on the work surface after the enamel dries. It usually allows you to estimate the content of water and solvents in the composition of the paint material.

The higher the hiding power, the lower the paint consumption.

The approximate volume is calculated using the following formula:

(Hiding power / Dry residue)*100

Example: You need to paint a wall with an area of 15 m2. With a covering capacity of 120g/m2 and a dry residue of 60%, the paint consumption per square meter will be equal to: (120/60) * 100 = 200 g/m2. We get the total consumption: 200* 15 = 3 kg.

Composition density

Let’s say the coating density is 1.4 g / cm3. To calculate the paint consumption per square meter, divide the mass (3 kg) by the density (1.4 g / cm3) and get 2.1 liters. This means that you will need 2 cans of paint of 1 liter each.

Depending on the type of base surface and the properties of a particular coating, this figure may be plus or minus 20%. For example, for painting concrete, as well as brick or plastered walls, you will need 10-15% more paint than for wood or metal surfaces (see the tables). To reduce the consumption of material, the walls can be pre-treated with a primer.


paint calculation formula

After the calculations are completed, we buy paint and start painting the room.

Before that, we check – have you forgotten anything?

It is very important to prepare all surfaces for painting beforehand. The walls must be leveled, cleaned to the required smoothness, carefully primed.

ATTENTION! Painting walls that are not ready for finishing will increase the consumption of paint and varnish material.

All calculations are based on the fact that the paint will fall on the prepared surface. If you are not sure of its perfection, after calculating the paint consumption, add a small percentage to the resulting value to avoid a shortage of material.

According to experts, if you need to paint decorative details, windows, door panels, you need to make additional calculations – according to the above formulas. The total area of the painted surface will consist of several components.

The areas of all walls, window sills, doors, ceiling, floor are calculated separately, which then need to be folded. Next, you need to find the paint consumption indicated on the package and calculate how much paint will be needed.

If different types of paints will be used for individual elements, then the area is calculated first, and only then the consumption of each of them.

But, you need to paint in two layers, we take into account the fact that with each layer the absorbency of the wall surface decreases, therefore, the paint consumption also decreases.

After all calculations, you will get the result in kilograms. Do not confuse with liters and keep in mind that domestic manufacturers indicate the consumption of paint in grams. In the final calculations, bring everything to a single unit of measurement.

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