How To Calculate Area
What is area?
Area tells us the size of a shape or figure. It tells us the size of squares, rectangles, circles, triangles, other polygons, or any enclosed figure.
In the real world it tells us the size of pieces of paper, computer screens, rooms in houses, baseball fields, towns, cities, countries, and so on. Knowing the area can be very important. Think of getting a new carpet fitted in a room in your home. Knowing the area of the room will help make sure that the carpet you buy is big enough without having too much left over.
Calculating Area
Area is measured in squares (or square units).
How many squares are in this rectangle?
We can count the squares or we can take the length and width and use multiplication. The rectangle above has an area of 15 square units.
Examples of calculating the area of a rectangle
Area = Length x Width Area = 3 x 2 = 6 square units 

Area = Length x Width Area = 8 x 6 = 48 square units 

Area = Length x Width Area = 9 x 5 = 45 square units 
Units for measuring area
We measure area using squares. We use different sizes of squares depending on how big or small an area is.
Size of the nail on your thumb  Millimeter  mm^{2} 
Size of piece of paper  Centimeter  cm^{2} 
Size of a room  Meter  m^{2} 
Size of a town  Kilometer  km^{2} 
We write square sizes using a small ^{2} next to the unit. We write mm^{2}, cm^{2}, m^{2} , km^{2}, cm^{2} We can say "63 millimeters squared" or " 63 square millimeters" 
We could use small squares to measure large areas. The only problem with this is that we would end up having to use very big numbers. For example, a field might be measured at 5,000,000,000 square millimeters when 5,000 square meters would be a much easier size to say, write, and visualize.
You will probably hear more units for measuring area; square inches, square feet, square yards, square miles, acres, hectares are all units used for measuring area.
More Examples of Calculating Area of Rectangles
Area = Length x Width Area = 9 mm x 4 mm = 36 mm^{2} 

Area = Length x Width Area = 7 cm x 6 cm = 42 cm^{2} 

Area = Length x Width Area = 8 m x 2 m = 16 m^{2} 

Area = Length x Width Area = 7 km x 5 km = 35 km^{2} 
Area of a Square
The length and width of a square are the same so we just need to multiply the length by the length.
Area = Length x Length Area = 6 cm x 6 cm = 36 cm^{2} 
Calculating Area Worksheets
Print out the worksheets listed below and use them for practice when learning how to calculate the area of squares and rectangles.
 Calculating Areas  Rectangles and Squares
 Calculating Areas  Rectangles
 Calculating Areas  Rectangles
 Calculating Areas  Rectangular Shapes
 Calculating Areas e.g. of Triangles
 Area of a Circle
 Calculating Surface Areas e.g. of Rectangular Prisms
You will find more printable geometry worksheets here.