A building's dimensions are established by measuring the distances around **the outer surface** of the exterior walls depending on the dominating section of **each wall**. The measurements include the width and height of a room or area.

These dimensions are important because they affect how a room is used. For example, wide rooms are usually considered to be public spaces while narrow ones are private. The same principle applies to heights: high rooms are considered public, while low ones are private.

The outer dimensions of a house are also important because they determine how much floor space there is inside. Ceiling heights and door openings also play a role in this calculation. If a house has two floors, then the first thing you should do is measure the exterior dimensions of the building. You will need to know the width of the house, the length from front to back, and the depth (height) of the house.

You can estimate the volume of a house based on **its surface area**. There are many ways to do this, but one simple way is to use the formula Volume = Surface Area x Height. For example, if you estimate that a typical two-story house is 100 feet long, 75 feet wide, and 45 feet deep, then it has an estimated volume of **450 cubic feet**.

When we draw a dimension from or to an outside wall, that dimension always travels to the outer edge (green dimension). When we size an inside wall, we usually assign the dimension to the wall's midline (purple). For us, the distances are more important than the actual sizes of the rooms. We know how far apart doors are expected to be from one another and from the walls.

The basic dimensions of a room are height, width, and length. Height is the distance between the top of the room and the ceiling. Width is the distance between **the right side** of the room and the left side of the room. Length is the distance from front to back of the room. You can also measure angles: height is also called headroom because you need space above your head to walk in the room; likewise, footspace is the amount of space below **your feet**. Width and length are also called room parameters because they describe the size of the room.

You can figure out the dimensions of a room by using mathematics and physics. The first thing to do is estimate the total volume of the room. This is easy if it is a box-like shape; otherwise, you will have to make some assumptions. Next, divide the estimated volume by the number of square feet in a square meter. This gives you the size of the room in **square meters** (m2). Finally, multiply this by 1,000 to get the size of the room in square feet (ft2).

Calculate the external dimensions of your structure, as shown in the figure above. The length and width of the building's walls should be measured. To calculate square footage, multiply the length and width values by two. Remember to double **the square footage** by the number of floors in **your facility** if it has more than one.

For example, if the wall length is 20 feet and the wall width is 10 feet, the total square footage is 200 square feet. If there are no additional walls inside the building, then it has 100 percent open space, which means that the volume is equal to the surface area. In this case, the calculation would be 200 square feet divided by 12 inches per foot, which equals 1680 square inches or 17 square feet.

You can also use the formula FSQ = FLOORING SURFACE DIAMETERS x NUMBER OF FLOORS. For example, if the flooring surfaces are 9 feet by 12 feet and there are 2 floors, the calculation is 96 square feet.

Finally, you can estimate the square footage by using the dimension tool in Google Maps. Click on the menu icon in the top-right corner of the map screen and select "Layers". Scroll down to the bottom of the list and click on the "Measurement" tool. Now, simply draw a box around your structure and Google will tell you how much space it is.