TaxQuarter lets you estimate your Australian tax refund or tax payable for the 2017/18 income year based on your income, expenses, PAYG withholding and PAYG instalments. Estimates are based on Australian resident rates and include the Medicare levy. Please note that TaxQuarter only provides an estimate of your tax refund or tax payable and your actual tax refund or tax payable will not be known until you receive your notice of assessment from the Australian Taxation Office.