How to calculate wall area: methods and examples

2024 Author: Aaron Duncan | [email protected]. Last modified: 2024-01-01 20:00

If you had to think about how to calculate the area of the walls in your apartment or house, then most likely you started a renovation. So, you will have to calculate the area of \u200b\u200bthe room in which the finishing work will be carried out. This is done mainly in order to calculate the consumption of finishing material for a certain amount of work. All measurements can greatly simplify the presence of a technical passport of the room, but for various reasons it may simply not be on hand. In addition, sometimes the dimensions indicated in the document may not match the real ones.

Measuring tools

In order to calculate the area of the walls in a room, you will need the knowledge once gained in elementary school lessons and prepare the most ordinary tools:

A sheet of paper in order to schematically draw the location of all walls, niches, doors and windows in a room or apartment

Pencil or pen.
Roulette. It is more convenient to use laserversion, but if there is none, then a regular mechanical meter will do.
Building cord or any thread to measure the radius if the room is round.
You will need a calculator to make the counting process easier.

Basic quantities

How to calculate wall area in square meters? Everything is simple. To do this, all measurements must be made in meters, because this is the main measure of area used in finishing work. Of course, you can measure everything in centimeters, but it will be extremely inconvenient due to too long numbers. In addition, when buying material, you still have to convert all measurements to square meters.

When calculating any area, the following indicators are used:

h is the height of the walls. For more accurate measurements (if required), it is recommended to measure the height in several places, and then find the average.
L is the length of the wall. For convenience, measurements are taken in the middle of the wall, but for more accurate calculations, measure the bottom, middle and top of the wall, add up and divide by three. It turns out the average length.
P is the perimeter. The sum of the lengths of all the walls of the room.
S - area. Measured in square meters.
π is pi, which is 3.14 (rounded).
R is the radius. Needed to calculate the area in round rooms or in rooms with rounded elements.

The area of the walls of a rectangular room

Probably the easiest option to measure. To do this, you need only two values:

Height and length. For the area of one wall S=h × L.
Height and perimeter. To measure the area of all walls S=h × P.

Example. For a room with wall length L₁=3.58m and L_{2=2.46m with height h=2.52m, the perimeter will be}

P=(L ₁+L_{2) ×2=12.08 m.}

This formula works with the same opposite walls, if all walls differ in length, then P=L₁ +L₂ +L ₃ +L_4.

Accordingly, the area of all walls will be equal to:

S=h ×P=12.08×2.46=30.4416 m².

Calculating the area of a rectangular room

And how to calculate the wall area in square rooms? In the same way: multiply the height by the length of the room and get the area of \u200b\u200bone wall:

S_{1=L ×h.}

Since the room is square, to find the area of all the walls you need to multiply the area of one wall by four:

S=S_{1 ×4.}

Calculation of a room with round elements

For rooms that have a round shape or semicircle elements, the calculation will be slightly more complicated, and will be carried out according to a slightly different scheme:

For fully round rooms, the calculation formula would be

First find the perimeter of the room

P=2 π R or P=π D, where:

D – diameter.

And in order to calculate the area of the walls, you need to multiply the perimeter by the height of the room S=P ×h.

For rooms with round elements, you need to schematically cut off the rounded part, thereby obtaining two figures. Then calculate the area of each element and add them up. As a result, we get the total areaall the walls in the room

Example. Room parameters: L₁=3.4 m, L_{2=4.1 m, h=2.52 m and R=1.54 m. The calculation procedure will be as follows:}

The perimeter of the first shape will be:

P_{1=π R=3.14×1.54=4.8356 m.}

Area:

S₁=P_{1 ×h=4.8356×2.52=12.1857 m².}

Perimeter of the second element:

P₂=(L₁ +L_{2) ×2=(3.4 +4.1) ×2 \u003d 15 m, and the area will be equal to:}

S₂=P_{2 ×h=15×2.52=37.8 m².}

Total wall area in the room:

S=S₁ +S_{2=12.1857+37.8=49.98 m².}

Calculating the area of an irregularly shaped room

Quite often there are rooms, apartments and houses with walls of non-standard shape. It can be all kinds of ledges, niches and columns or walls that create various shapes with their construction.

How to calculate the area of the walls in this situation? Yes, everything is the same, despite the non-standard forms, the approach to calculating their area is quite common.

First, you need to schematically divide the room so that you get different geometric shapes. We calculate the area of each of them, and then add them up, thereby obtaining the total area.
Another way to calculate the area, but it is not always convenient, due to piling up furniture for example. It consists in the fact that you need to pass a tape measure along all the walls (of any shape) in a circle. That is, starting to measure from one corner to it andreturn. Having received the total perimeter, multiply it by the height and immediately find the total area of the room.
Another type of irregularly shaped wall is the attic. In this situation, the wall is schematically divided into a quadrilateral and a triangle. Depending on which triangle is obtained (rectangular, isosceles or equilateral), various formulas are used to calculate the area.

For example, for a right triangle:

S=½ab where:

a and b are sides forming a right angle.

Or you can use Heron's formula:

S=√p(p-a)(p-b)(p-c), where:

a b c are the sides of the triangle, and p is the semi-perimeter a+b+c ÷2, which allows you to calculate the area of a triangle from three sides.

And how to calculate the area of the walls of a house or apartment? The answer is even easier than the question. We find the area of each room separately and their sum will be the area of the apartment or house.

Subtract windows and doors

If we want to calculate the area of the walls correctly, then it is impossible to do without this action. Windows and doors, or rather their size, give a large error in the calculations, if you do not subtract their area. The calculation of the area of window and door openings does not differ from the calculation of the area of walls and looks something like this:

you need to multiply the height and width of the window or doorway, thereby obtaining the area.
then add up the areas of all openings and subtract the result from the area of the room.
the answer received will be the most accurate.

Example. In a room of 43.8 m² there area window opening measuring 2.1 by 1.45 m and a doorway measuring 0.9 by 2.07. By calculation, we obtain a window area of 3,045 m² and a door area of 1,863 m². Adding the results, we get the total area of the available openings equal to 4, 908 m². Now subtract these numbers from the area of the room and get a more accurate result:

S=43, 8-4, 908=38, 892 m², where:

S is the area of all walls without windows and doors.