To calculate an object's square footage, first measure the height and length. Ensure the height and length have the same units, then multiply them together to find the square footage.
If an object is rectangular, its square footage can be calculated by multiplying the height and length together. Note that the height and length must have the same units when multiplying together, such as inches, feet, centimeters or meters. For complex units of length, first convert them to a simple unit of length such as inches or centimeters before multiplying the height and width together. The square footage will be in square units depending on what units were multiplied together, such as square inches and square feet.