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How to calculate total internal area of a house?

I am trying to find out the total internal area of my house. Does this mean I have to add up all the rooms and add them or just measure the total area of 1 floor and multiply by 2 (as the house is 2 floors). Also do I include the area of the loft? It is a storage loft with light. Not a living space.



Here are a few tips for calculating the total internal area of a house:

  • Measure each room individually. Get the length and width and multiply them together to get the area for that room. Include all spaces like bedrooms, bathrooms, living rooms, kitchen, hallways, etc.
  • For rooms with an irregular shape, divide them into simple rectangles/squares and calculate each segment separately then add them up.
  • Add up the total area of each floor. So measure every room on the first floor and add up all the areas. Do the same for the second floor and any additional floors.
  • Basements count if they are finished livable spaces. Do not include unfinished basement areas.
  • Attached garages are not included in the internal livable space. Only measure garage if it has been converted to a living area.
  • Storage lofts are generally not included unless they have been converted into usable living space with proper flooring, lighting, etc.
  • Make sure to convert all measurements to the same unit (feet or meters) when calculating.
  • Double check by roughly multiplying length x width of the overall structure as a sanity check on your detailed room-by-room calculation.

So in your case, do not include the unfinished storage loft. Calculate each room individually per floor and add them up to get the total internal area. Keep units consistent and double check against a rough overall calculation. Let me know if you have any other questions!

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