Direct taxes are calculated from taxable income, which will be either revenues less deductible expenses, or, under the percentage of revenue option, generally 40% of revenues. You can keep accrual or simple accounting books and still use the percentage of revenue method. Health and social insurance, meal and entertainment expenses, or poorly-documented expenses are not deductible. Both health and social insurance taxes max out at 1,809,864 CZK of taxable income.