What is the basis for social security contributions to tax

Individual tax is calculated based on the monthly salary earned by the individual, if the amount of income is already the amount of income after deducting social security costs, the method of calculation of individual income tax is: individual income tax = taxable income × applicable tax rate - quick deduction. The starting amount of personal income tax is 3500 RMB, taxable income = personal income (after deduction of social security expenses) - starting amount = personal income (after deduction of social security expenses) - 3500; the applicable tax rate and the number of quick deductions need to be selected according to the range of taxable income: the tax rate for taxable income not exceeding 1500 RMB is 3%; the tax rate for exceeding 1500 RMB but not exceeding 4500 RMB is 10%,; the rate for more than $4,500 but not more than $9,000 is 20%.

Legal basis:

Methods for Calculating Individual Income Tax of Individual Industrial and Commercial Households Article 3 Individual Industrial and Commercial Households referred to in these Measures include:

(1) Individual Industrial and Commercial Households that have obtained the Individual Industrial and Commercial Households Business License according to the law to engage in the business of production;

(2) Individuals that have been approved by the governmental departments concerned to engage in the activities of running schools, medical treatment, consulting and other remunerated service activities;

(iii) other individuals engaged in individual production and business.