To calculate your fuel tax credit claim, you start by identifying what fuel tax credit rates apply to your eligible fuels and business activities. There are different fuel tax credit rates depending upon the fuel type and the use.

The fuel tax credit rates apply to fuel used:

• in heavy vehicles for travelling on public roads
• for all other business uses.

When you claim fuel tax credits, you must use the rate that applied on the date you acquired the fuel.

The ATO website has the current fuel tax credit rates and past fuel tax credit rates. Fuel tax credit rates change regularly, so it's important to check and apply the correct rate. You must claim fuel tax credits within four years. The four years starts from the day after you were required to lodge the BAS for the tax period in which the fuel was acquired.

Fuel tax credit rates are:

• indexed based on the upward movement of the consumer price index twice a year, in February and August
• the biodiesel rate is increased annually on 1 July
• the road user charge is usually changed in July and this affects the cost of fuel used in heavy vehicles for travelling on a public road.