How to calculate the social security payment base of 20 17?

Generally, my salary income in the previous year is the base of payment:

If the wage income of employees is higher than 300% of the local average wage of employees in the previous year, 300% of the local average wage of employees in the previous year shall be the payment base;

If the wage income of employees is lower than 60% of the local average wage of employees in the previous year, 60% of the local average wage of employees in the previous year shall be the base of payment;

If the wages of employees are between 300% and 60%, they shall be declared according to the facts. When the wage income of employees cannot be determined, the payment base shall be determined according to the local average wage of employees in the previous year published by the local labor administrative department;

Social security will regularly check the base every year (March or July, in different places), and declare a new base according to the average monthly salary of employees in the previous year. It is necessary to prepare proof of these payroll.