How to calculate the perimeter of a room?

During the repair, a situation may arise when you need to know the exact perimeter of the room, for example, when buying a skirting board or when calculating the number of wallpapers and flooring. This is easy to do if the room has a standard shape. But what if we need to calculate for the corridor, which has many angles, or for the bedroom of an unusual shape? In this process, some tricks will help, which you can resort to repair planning.

Calculation for standard rooms: square and rectangle

Most often there are rooms whose walls form a rectangle or square. In this case, we need:

• roulette;
• ruler;
• thread;
• paper and pencil.

First, let's recall what a perimeter is. This is a geometric quantity, which is the sum of the lengths of all sides of the figure. Calculating it is even easier than floor area.

The simplest case is a room, which is a square, that is, all its sides are equal. Then we measure one side of the square, putting the tape measure at the junction of the wall and the floor.

If you don’t have a tape measure, use a thread, making a line corresponding to the distance from the corner to the corner of the room, and measure it with a ruler.

The desired value can be calculated by multiplying the measurement result by 4. So, for a bedroom that has a square shape with a side equal to 5 meters, the perimeter will be equal to:

5 x 4 = 20 (m)

A little more interesting when the room is a rectangle. This means that the lengths of the opposing walls are equal. In this case, we measure the distance from the corner to the corner of two adjacent walls with a tape measure, add the obtained numbers to each other and multiply by 2. For clarity, consider an example: a rectangular living room is given, the length of one of its walls is 5 meters, the other 5.5 meters. Then the perimeter will be:

(5 + 5.5) x 2 = 21 (m)

Do not forget that even with an accurate calculation of the number of building materials, you need to buy them with a small margin in case of damage.

Custom options: polygon and circle

It is easy to calculate the perimeter when the opposite sides of the figure are equal to each other. Let's complicate the situation: the existing kitchen has more than four corners. In this case, you will have to measure each segment from one angle to another, and then add up all the measurement results. This method differs from the previous one in that in order to calculate the perimeter, you need more source data.

Take a hexagon-shaped kitchen with a niche. Then the number of walls that we have to measure, then adding up the obtained values, will be equal to 8.

We complicate the situation even more: the hall is a circle. Here measurement from corner to corner does not help, since they simply do not exist. If there is confidence that this is really a circle, not an ellipse, then knowledge of geometry will help. The perimeter is the circumference. And the circumference, in turn, is the product of the diameter of the circle by the number π.

It sounds scary, but it's really simple.

1. Find the center of the room and designate it.
2. We fix the thread near one wall and draw it to the opposite through the center of the room.
3. We measure the length of the obtained segment. This is the diameter of the circle.

Now you need to count. We take the resulting diameter and multiply by the number π. Everyone knows that this number is infinitely large. But we do not need accuracy to the hundredth of a millimeter, so we take 3.14. Thus, the perimeter of the circle is the length of the segment from wall to wall through the middle of the room, multiplied by 3.14.

So, having a round room with a diameter of 5 meters, we get the value we need as follows:

5 x 3.14 = 15.7 (m)

Useful Tips

What to do if you absolutely do not want to count or not want to crawl around the room, measuring the wall with a tape measure? There are some useful tips:

• Take a laser roulette from a friend. With this device, it will be possible to carry out all measurements on your own, unlike roulette, when using which you need a friend who holds its end. In addition, the device will give a more accurate result, since the laser beam will not deviate. This will help to more accurately calculate the perimeter of the room.
• Use a long thread. It will be much more convenient to fasten parts of the thread to the corners, without interrupting the measurement. The thread should be unwound until it meets its own end - the beginning of measurement. Its final length - this is the desired value. This method will help if there is an ellipse-shaped room, since it will be problematic to calculate the length of this figure in a different way.

Thus, in a short time, you can carry out all the necessary measurements and get the finished result. However, it is worth remembering that as a result, it is necessary to take into account the error so as not to purchase building materials less than necessary. For example, if the wall is uneven, even with accurate calculations, you will need more skirting boards to smooth out the flaws.