Under the ATO's PCG 2016/8, businesses need a fair and reasonable way to apportion fuel use where some fuel is claimable and some is not. In practice, this is usually done using one of three approaches: constructive, deductive, or estimated use.
Method 1: Constructive method
The constructive method builds the claim from the ground up by identifying eligible fuel use directly.
Typical approach:
- Start with fuel acquired and used in the BAS period
- Link fuel use to specific assets, activities, or operating contexts
- Apply the relevant FTC treatment to each identified use category
This method is generally strongest where you have detailed operational data and want high confidence in how each litre is treated.
Method 2: Deductive method
The deductive method starts with total fuel and removes non-claimable or excluded portions.
Typical approach:
- Start with total fuel acquired for the period
- Deduct fuel amounts that are not claimable
- Claim FTC on the remaining eligible balance
This is often practical where exclusions are easier to identify reliably than every individual eligible use.
Method 3: Estimated use method
The estimated use method applies a documented, fair and reasonable estimate to determine claimable portions.
Typical approach:
- Use representative operational data or sampling
- Derive an eligible-use percentage (or equivalent factor)
- Apply that percentage to relevant fuel volumes
This method can reduce manual effort where direct allocation is difficult, but it requires clear assumptions, supporting evidence, and periodic review.
How GPS data supports apportionment methods
For methods where the taxpayer must ascertain fuel apportionment, GPS and telematics data can materially improve both evidence quality and workflow efficiency.
GPS-based data can support:
- Constructive method outputs through trip- and asset-level activity classification
- Deductive method outputs by evidencing excluded vs eligible operating contexts
- Estimated use methods by generating defensible apportionment factors from real operating history
In practice, this can help improve claim value by reducing over-conservative assumptions and identifying eligible use that may otherwise be missed. It can also reduce process workload through repeatable monthly calculations, stronger audit trails, and fewer manual reconciliations.
Choosing a method
In practice, most teams choose based on:
- Compliance confidence
- Data availability and quality
- Operational effort required each BAS cycle
- Audit traceability
Choosing the right method for your business depends on various factors including the size of your asset base, the complexity of your fuel uses and operations and the tools and data available to you.
Adjustments and reviews
If business use patterns, vehicle mix, or data quality change, review your method and assumptions. FTC calculations should be treated as a controlled process, not a one-off setup.