The expansion fee of budgetary estimate refers to the difference in transverse amplitude between budgetary estimate quota and budgetary estimate quota, and the difference in design depth between preliminary design drawings and construction drawings. Therefore, it is necessary to appropriately expand the cost when compiling. The calculation base of expansion cost is the partial cost of budget estimate+total comprehensive cost, and the expansion coefficient ranges from 1%~3%. 1% when the project is simple or the design depth of the drawings meets the requirements, and 2% when the project is generally difficult. However, if you are not solid enough, I recommend you to go to Hangzhou Gaobo for education and training, which is very beneficial to your career and ability improvement.