How to Calculate Square Meter: Rectangles, Conversions, and Complex Shapes

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Square meter

Another day doing math, and another day trying to solve formulae and calculate stuff. Among all the head-ache-inducing formulae that you may come across in maths, square meters stand at the very top of the list. We have created a small step-by-step guide to help you understand the method to calculate square meters.

But before we dive straight into how to calculate square meter and the square meter formula you need to use, you need to understand what is a square meter:

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What Is a Square Meter?

A square meter can be defined as the area equivalent to a square that is 1 meter on each of its four sides. Square meters are used to measure the areas of houses, blocks of land, rooms, etc. In other words, square meters are a measurement of an area and are typically used to measure a 2-D space like a floor or a field. The symbol used for square meters is m2.

For instance, you can use square meters to calculate the footprint of a sofa you saw at IKEA on your way home, and then measure your lounge’s area in square meters to see if the sofa will fit in or not. You do not need any special tools to measure square meters, even if you have a measuring tape or a standard ruler that measures in feet or some other non-metric unit, you can still measure the area with it, and then convert the answer to square meters.

How to Measure an Area in Square Meters?

First of all, you are going to need some appropriate equipment. Choose a metric tape measure or a meter stick. When looking to buy a tool, go for a tape measure or a meter stick ruler with centimeters (cm) or meters (m) printed on it. Using these tools can make it easier for a beginner to calculate square meters because they are also designed in a similar system of measurement.

But if you cannot find the said equipment and you only have a ruler with inches (in) or feet (ft) printed on it, use that to measure the square meters. You can then later convert your calculations to square meters. Now, start measuring:

  • Once you have your tools, begin with measuring the length of the area you are interested in. Use your measuring tape or ruler to measure one side of the room or the object under consideration, and measure from one corner to the other corner. Note down the measurement.
  • If your area is longer than 1 meter, then you must include both parts of the measurement – the meter and the centimeter. For example, 2 meters 35 centimeters. Or if your object is not the area of a square or rectangular, keep reading, we have covered complex shapes below.
  • If your object is too big to be measured all at once, then measure the length in stages. Lay your ruler or measuring tape out and place a rock or a paperweight at a mark that you can easily remember such as 25 centimeters or 1 meter. Once you measure up to that distance, pick your mark and lay it down again. Keep doing this until the total length has been measured, and then add all your smaller measurements together to get the total length.
  • Another smart way is to break your room into small rectangles if your room or object is not rectangular. For instance, if your living room is L-shaped, you can divide it into 2 rectangles (non-overlapping).
  • Once you have the length, start measuring the width. Use the same equipment that you used to calculate the length. However, for the width, the side you measure needs to be angled closer to 90º far from the length you recorded earlier, just like 2 sides of a square right next to each other. Note down this measurement as well.
  • You can also round off to the nearest centimeter when taking the measurements unless your object is much smaller than 1 meter. For example, if the width of the object you are measuring is a little more than 1 meter 8 centimeter, then just write down ‘1m 8cm’ as your measurement without any millimeter measurements or going into decimals.

Now, it is time for the conversions:

Convert into meters from centimeters and remember that your measurements will not evenly divide into meters. So, you will get a measurement in meters and centimeters, for instance, 2 meters 35 centimeters.


1 centimeter = 0.01 meters

So, you can convert centimeters into meters by moving the decimal point to the left by 2 digits. 

Let’s convert 2 meters 35 centimeters to just meters:

  • 35cm = 0.35m
  • Therefore, 2m 35cm = 2m + 0.35m
  • Which means that 2 meters 35 centimeters = 2.35m
  • And 1 meter 8 centimeters will be 1.08m

Then multiply the length by the width after you have converted them both into meters. The result of multiplications will be your measurement of the area of your object in square meters. You can use a calculator if you like.

Let’s use our above measurements;

2.35m x 1.08m = 2.538 m2 (square meters)

You can round it off to the nearest number for your convenience. Thus, 2.538 square meters will become 2.54 square meters when rounded off. In fact, owing to human error, you most probably didn’t measure the sides of the object, to the tiniest fraction of a meter, correctly, so your last digits aren’t approximate anyway. Hence, you can just round off to the nearest centimeter (0.01m).

Keep in mind that when you multiply two numbers with the same SI units, your answer will always have the squared form of that unit. For example, meters will turn into square meters or m2.

How to Convert From Other Units?

Here is how you can convert into square meters if you are working with different units:

Square Feet

If your measurements are in square feet and you want to convert square feet to square meter, then you need to multiply the former by 0.093. Measure the length and width, with the equipment at hand, in feet and multiply them together to get the area of the object in square feet.


1 square foot = 0.093 square meters

You will have to multiply your answer by 0.093 to convert it to square meters. For a more precise conversion, multiply by 0.092903.

Square Yards

If your measurements are in square yards, then you will have to multiply them by 0.84 to get your answer in square meters.


For measurements that are in acres, you will have to multiply them by 4050 because:

One acre = 4050 square meters.

If you want to achieve greater precision in your answer, then multiply by 4046.9.

Square Miles

First, convert square miles to square kilometers because 1 square mile is way too large than 1 square meter. To convert square miles into square kilometers, multiply the former by 2.6 or you can multiply by 2.59 for more precision.

And then to convert to square meters use:

1 square kilometer = 1,000,000 square meters.

Note: Do not use the above calculation to convert units of length to units of the area because square meters are a unit of area. So, it won’t make sense to compare areas and lengths or widths.

Calculating Square Meters for a Complex Shape

Once in a while, you may come across a shape so complex that you are unable to figure it out at first. If you have a complex shape, make an outline of it and break it into smaller shapes like triangles and rectangles. 

Follow our instructions to find the area of a complex shape: 

  • Start with rectangle-shaped pieces and follow the instructions above to find their areas in square meters. 
  • Then move on to right triangles and divide by two. A right triangle with a 90º angle is similar to the corners of a square. And it can be easily measured to calculate its area. Measure the two sides adjacent to the 90º corner and multiply them and then divide by 2 to get your area in square meters. This method works because a right triangle is equal to a halved rectangle. Hence, you just find the area of a rectangle and divide it by two to get the triangle’s area.
  • Turn other angle triangles into right triangles as well, then measure them. Draw a line from the triangle’s corner to the opposite side, so the line reaches the opposite side at a right angle. This way you can divide a triangle into two pieces, and each piece is a right triangle. Follow the same instructions in the above bullet point and find the area of the two sub-triangles individually and then add them together.
  • After you are done with the triangles, calculate the area for the circles. The formula for the area of a circle is πr2, where; r = radius. Measure the radius by measuring the distance from the center of the circle to the perimeter. Multiply this distance by itself and then multiply the result by π. If you do not have an advanced calculator, multiply by 3.14 or 3.1416 for higher precision. If you cannot determine where the center of the circle is, ask your friends to hold a measuring tape and walk around the perimeter of the circle. Hold the other end of the measuring tape and adjust your position to keep the measurement the same while your friend walks around the circle’s edge.
  • Keep in mind that more complicated curved boundaries need more advanced math to determine their areas. Thus, if you come across such boundaries when measuring a room, calculate the area by pretending the curved surfaces are straight lines.


It is your turn now!

It might feel difficult in the beginning but once you get the gist of it all, then measuring, calculating, and converting will feel like a piece of cake. Don’t let complex shapes and square meters scare you away. You have got this!

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Austin has 10+ years of experience in teaching. He has researched on thousands of students-related topics, issues, and concerns. You will often find him writing about the common concerns of students, their nutrition, and what is beneficial for their academics and health both.