The PIT-36 declaration, referred to in the Act of 26 July 1991 on personal income tax (Article 44), is a form used for the annual settlement of personal income tax for individuals who earn income from business activity, rental, lease, and other sources that require keeping accounting books. Its purpose is: Annual income tax settlement – enables calculation of the income tax due based on income earned and deductible costs. Reporting reliefs and deductions – allows claiming applicable tax reliefs and deductions, which may reduce the tax liability.