Finding the gross amount of square footage in your home is easy if it is square or rectangle, but some rooms may not qualify for inclusion in your calculations. To start the process, multiply the length by the width of your home. You can double the result initially if you have a two story home, and then plan to deduct open space on the second floor for the stairway. Create a drawing of the perimeter of your home so that you can calculate the space of areas that are outside of its basic square or rectangular shape.

Complying with Standard Requirements

Four specifications define what you can include as square footage, and meeting one, two or three of the requirements is not enough. Your home must comply with all four of the specifications to produce a legitimate number that is acceptable.

1. Space Occupied by Humans

Often referred to as “living space”, the area in your home that is fit for occupancy by people qualifies for inclusion in square footage calculations. Space that is intended for human occupation provides creature comforts that are generally accepted features of a home.

2. Presence of a Heating and Cooling System

To indicate the permanence of space that is occupied by people, a home must have a conventional heating, ventilation and air conditioning (HVAC) system. A home that does not have a permanent way to provide heated or cooled air is not considered as a typical space for human occupation.


3. Use of Traditional Building Materials

Floors, walls and ceilings must have coverings that are typically used for interior construction. If your home has rooms with bare concrete floors, open ceilings that reveal roof supports in the attic or unfinished wallboard, you cannot include them in your square footage.

4. Direct Connection to Another Finished Area

Each room that is counted in square footage must directly adjoin another room that is finished with traditional construction materials and methods. Access to a finished room from one that is not equally complete eliminates it from your calculations.


Handling Special Circumstances

Stairways, closets and hallways are included in square footage, but basement and attic rooms are usually excluded.

Requirements that apply to these special circumstances include:

• Stairways

The upper area of a stairway is usually larger than the entry on the lower area, and calculations of the floor space for a second floor must not include open space. Calculate the area of the opening and deduct it from the total for that floor.

• Closets and Hallways

When halls and closets are used as part of the functional living space of your home and they comply with the standards that apply to other areas, you can include them in your square footage.


• Basements

Finished rooms in your basement do not generally comply with the standards for calculating square footage. The lack of windows is a detriment in a space that is meant for human occupation, and having only one escape route in case of fire or flood is another disqualifying element. A finished basement may add some value to your home when a real estate agent compares it to another that may not have one, but it is best not to include it in your calculations.

• Attics

Finished rooms in your attic have the same disqualifying characteristics as those in your basement.

However, if your home is an A-frame or a chalet-style structure, some rooms may qualify as acceptable attic space. They must meet the requirements for living space, but a sloping roof limits the amount that is usable.

To get a fair estimate, include only the area where a five foot person can stand erect. If the majority of a room, 50 percent or more, does not have a ceiling that is at least seven feet high, then you cannot include it.


• Utility Rooms

Storage rooms for your water heater, furnace or other utility items are included in overall square footage. They may not have appointments that are as elegant as those in other areas of your home, but you can include them if they meet the requirements for living space.

• Excluded Spaces

Areas that are not available for inclusion in your square footage calculations include your garage and attached deck, guest house, and exterior porches.

By carefully measuring the dimensions of your home and evaluating the suitableness of rooms for occupancy by people, you can get a reasonable approximation of the square footage in your home