The square footage of a rectangle measures the area. You might need to calculate the square footage of a rectangle to find the size of a room or the amount of sod you need for putting grass in your yard. Once you know the formula for finding the area of a rectangle, calculating the square footage is a breeze.
Measure the length of the rectangle in feet with a measuring tape.
Measure the width of the rectangle in feet with a measuring tape.
Multiply the length times the width to find the square footage of the rectangle. For example, if the length equals 3 feet and the width equals 2 feet, multiply 3 feet by 2 feet to get 6 square feet.