How much paint does it take to paint the walls?

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One of the components of a competent repair is saving time, finances and resources. We decided to paint the walls – plan everything in advance and calculate how much paint does it take to paint a room? We will tell you how to do everything as accurately as possible – taking into account all the necessary factors and preparatory work to give you an idea on how much paint does it take to paint a room?

What is planning and calculation for paint?

Even if you are far from the exact sciences, having conceived paint and varnish works, you will have to be prudent and scrupulous. If you incorrectly calculate the required amount of material or how much does it take to paint a room, you will face a number of problems. You will have to go to the store and buy additional paint – the same color and manufacturer. It will be unpleasant if the necessary 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 shouldn’t exceed your budget. 

Why count and what to consider to know how much does it take to paint a room?

Such a question can be asked by those who have already entered the store, figured out what and how much he wants to buy for painting a room wall, 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 package, and secondly, accurate calculations cannot be made based on these data, a number of other factors must also be taken into account to calculate how much paint does it take to paint a room?

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 for painting a room?
• 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?

Tools For Painting

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

• rollers. medium pile length is used to create a simple relief, short pile is suitable, for example, for the effect of a stone wall;
• spray gun.  suitable for all sorts of experiments and the embodiment of design ideas;
• wide tassel.  the need for it arises when creating various kinds of textures, for example, to create the effect of aging;
• sponges, trowels.

The most economical in terms of paint consumption from the above list is a spray gun. This tool at one time became a real breakthrough in the construction world. A spray gun, or paint gun, is able to distribute paint in a thin, even layer, which can significantly reduce material consumption. Compared to a conventional brush and roller, it uses two or even three times less painting material. In addition, the staining process itself takes much less time.

The most wasteful method is applying paint with a brush: different layer thicknesses, drips, 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 economical and lays down evenly.

Original surface color and texture

The original 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. 

Further – it is important to know what “paint hiding power” is. In short, this is the ability of the material to overlap the color of the substrate when applied uniformly in one coat.

Hiding power – the ability of a pigment or pigmented paint and varnish material, when evenly applied to a surface, to make the color of the latter invisible, or, if applied to a black and white surface, to reduce the contrast between black and white areas of the surface until the difference in lightness between them completely disappears.

The higher 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 paint consumption, 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 the cement, respectively, more paint will be required.

Also the following table is a helpful reminder.

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

metal	14-16 m2
plaster	16 m2
polished wood	16 m2
embossed wallpaper	10 m2
freshly sawn tree	8-10 m2
primed plaster	15-17 m2

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Paint color

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

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

Typically, 1 kg of paint is enough to paint the following surface:

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

The types of paints differ from each other in their structure, respectively, to paint one square meter of area, a different volume of material is used.

Which paint is better to choose to paint a room? – acrylic, enamel, etc. – is a separate topic. In short, the composition of the surface that you need to paint is important. For example, acrylic paint is usually used for the ceiling. 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.

TYPE OF PAINT	CONSUMPTION PER LAYER kg / m2	CONSUMPTION FOR THE 2nd LAYER kg \ m2
Acrylic	0.25	0.15
Silicone	0.30	0.15
Silicate	0.40	0.35
Polyvinyl acetate	0.55	0.35
Latex	0.60	0.40

BASIC CALCULATIONS For how much paint does it take to paint a bedroom?

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

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

We will clearly show how to do this.

How to find out the total surface area to paint?

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

STEP 1. 

Using a tape measure, 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 .

STEP 2. 

Now measure the height (c) of the walls 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.

We know the surface area that we will paint. But door and window openings are not taken into account: they must be subtracted from the resulting area.

STEP 3. 

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

STEP 4. 

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 for room?

So, we know the area. To calculate paint consumption, you need to divide the area by the standard consumption. As a result, we will get a figure for 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 watch the standard consumption:

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

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

S * consumption per m2 = paint consumption per room

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

This is an indicator provided that it is painted in one layer.

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

Example of calculating paint consumption. Calculation of paint consumption when painting one wall of an ordinary room. We calculate the total area of ​​the room, then subtract the area of ​​the 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. Subtract the door area (2 m2) from the total area (12 m2). The surface area for painting is 10 m2. Next, we find out the required amount of paint. For example, a can of paint with a volume of 2.5 liters is enough for painting in one layer of an area of ​​25 m2. Total: for a wall with an area of ​​10 m2 for painting in 2 layers, you will need 1 can of paint of 2.5 liters.

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We calculate the errors

Hiding power and dry residue

These figures are usually indicated on branded products. 

Dry residue – those substances that remain on the working surface after the enamel dries. Usually it allows you to estimate the water and solvent content in the composition of the paint and varnish material.

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

The approximate volume is calculated using the following formula:

(Opacity / Solids) * 100

Example: You need to paint a 15 m2 wall. With a covering power of 120g / m2 and a dry residue of 60%, the paint consumption per square meter will be: (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 consumption of paint 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, 1 liter each.

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

Final Conclusion

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 pre-prepare all surfaces for painting. The walls should be leveled, cleaned to the required smoothness, and carefully primed.  ATTENTION! Painting walls that are not ready for finishing will increase the consumption of paints and varnishes. 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.
• If you need to paint decorative details, windows, door panels, you need to do additional calculations – according to the above formulas. The total area of ​​the surface to be painted will consist of several components.
• The areas of all walls, window sills, doors, ceilings, floors are calculated separately, which must then be folded. Next, you need to find the paint consumption indicated on the package and calculate how much paint is required. If different types of paints are used for individual elements, then the area is first calculated, and only then the consumption of each of them.
• If 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 the calculations, you will receive the result in kilograms. Do not confuse with liters and keep in mind that domestic manufacturers indicate paint consumption in grams. In the final calculations, bring everything to a single unit of measurement.