Under a Chattel Mortgage car finance contract, the total GST applied to the purchase price of the vehicle is claimable by the buyer on the next ensuing BAS return if the buyer is registered for GST. As the full amount of GST relating to that vehicle has then been accounted for, GST is not applicable to the monthly repayments or the balloon. GST is not applied to the interest component of the finance. When entering the loan amount in the calculator, you can enter the full purchase price of the vehicle including the GST component. The repayments will be calculated based on that figure including the GST less any balloon amount if selected. GST is not shown separately or itemised in the calculator functions. If you would like to calculate repayments for the ex-GST price of a vehicle, simply enter that amount in the loan amount field. Some car dealers and manufacturers will advertise a purchase price plus GST.