Pension contributions made through payroll are deducted first from gross pay and the remainder is your taxable pay. PRSI is then calculated on taxable pay as explained . Gross tax is also calculated on taxable pay and then your tax credits (listed on your annual statement of tax credits from Revenue) are deducted from the gross tax amount to give a figure for net tax. Your net pay is then gross pay minus (pension contributions plus PRSI plus net tax). Does that make sense to you? [broken link removed] might be of assistance in sanity checking your payslips/deductions. If you can't use the calculator and want to post your own personal figures (e.g. gross salary, frequence of payment - weekly, fortnightly, monthly, tax credits, pension contribution, tax band) then somebody will probably be able to calculate what your deductions and net pay should be.