Then calculate the average monthly salary of social security.

The employing unit shall truthfully report to the local tax authorities the social insurance payment base of the insured employees in the next social security year according to the average monthly salary of the insured employees in the previous year. After the annual declaration, in a social security year, if there is no special change in the insured, the payment base will remain unchanged. The average monthly salary of employees in the previous year is the monthly average of the total wages of employees in the previous year. The total wages of employees are composed of six parts: hourly wages, piece-rate wages, bonuses, allowances and subsidies (except for travel subsidies, missed meals subsidies and one-child subsidies), overtime wages and wages paid under special circumstances. Local and foreign workers are calculated according to this method, and the specific base of each type of insurance is determined by the local tax department according to the average monthly salary and policy of the previous year declared by the unit.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.