Measure the length of each room or area in feet
Measure the width of each room or area in feet
Multiply length by width to get the square footage of each rectangular area
Add the square footage of all rooms and areas together
Include closets, hallways, and other finished interior spaces if counting total living area
Exclude garages, unfinished basements, porches, and other non-living spaces unless specifically needed
For irregular shapes, break the area into smaller rectangles, calculate each one, and add them together
For triangular areas, multiply base by height and divide by 2
For circular areas, multiply pi by the radius squared
Verify all measurements and total them for the final square footage