How to calculate the property fee for buying a house, including what area?

At present, basically, the billing area of property management is based on the construction area indicated in the real estate license. The construction area includes two parts: one part is the interior construction area, and the other part is the common area. Houses that have not yet obtained the real estate license shall temporarily be subject to the sales area on the purchase contract signed by the developer and the purchaser; The construction area measured by the housing survey department and written into the real estate license shall prevail. At present, in order to avoid the area disputes in the sale of commercial housing, some cities stipulate to sell houses according to the interior construction area or interior usable area, that is, by raising the unit price, the total house price will remain unchanged, so that consumers can clearly understand the purchase and the purchased area will be more clear. For such a residence, the billing area of property management is based on the area specified at the time of sale (interior construction area or usable area).