The purpose of this paper is to provide an overview of income tax, emphasizing the specifics of income from self-employment with reference to non-payment of wages. Income tax is a key element of the tax systems of modern countries, and it is determined according to the provisions of the Income Tax Act. Calculated as the difference between receipts and expenditures within the tax period. Final income represents income that is taxed after the end of the tax period without the possibility of subsequent correction or transfer to the next period. Annual income includes all income and expenses within the tax period, allowing for adjustments and corrections that may affect the final tax liability. Income from self-employment refers to wages and other forms of income that employees receive from employers. This income is subject to a special method of tax calculation. In general, self-employment income includes regular wages, bonuses, and other compensation that an employee receives for work performed. Personal deduction is the amount that is subtracted from the total income when calculating taxes, enabling a reduction of the tax base and relief for taxpayers. The paper presents an example of salary payment that illustrates the method of calculating gross and net salary, including tax obligations and the application of personal deduction with the JOPPD form, which helps in understanding the actual financial obligations of employees.