The average retail costs of unleaded petrol (expressed as cents per litre) for the 2012-13 income year are provided below. Taxpayers can use these figures to calculate the fuel deduction where receipts have not been kept to substantiate a claim, provided a valid logbook is kept and the other requirements under the law are met.

As a general rule, taxpayers may use either a reasonable estimate or actual receipts when claiming a deduction under the one-third method or the log book method for car expense deductions.  According to a Tax Office determination, where actual receipts have not been kept, it will accept a reasonable estimate of average fuel costs and fuel consumption based on the business kilometres travelled for these methods.

The figures below have been compiled using monthly data for regular unleaded petrol, collected by the Australian Automotive Association. Users of premium fuel or diesel may need to determine the price differential from retailers in their area.  Similarly, a different average may apply to taxpayers living in remote or rural areas.