Flat tax is a form of taxation in which income, regardless of its amount, is taxed at a fixed unchanging percentage rate. This means that all individuals pay the same percentage of their income as tax, regardless of whether they earn little or a lot. In Poland, the flat tax is 19% and is one of the taxation options for entrepreneurs, including sole traders. This form of taxation is often chosen by those with higher incomes, as it can prove more beneficial than a tax scale with higher rates for higher incomes. The flat tax is also popular with freelancers and freelancers.