How to calculate the bay window area of self-built houses?

The height from the floating windowsill to the ceiling is less than 2.2m The windowsill is not included in the area, and the building balcony should be calculated according to its horizontal projection area 1/2. Floor-to-ceiling windows over 2.2 meters effectively expand the actual use area of the house, so it should be included in the property area of the house, and the house price should be calculated according to the final measured area.