Fuel consumption calculator (L/100km)
By Sithum Imarsha Last reviewed
For an example fill, 500 km on 40 L is 8 L/100km, or 12.5 km per litre. At 237.5c a litre that is 19.0c per km.
Your result
Your fuel use
8L/100km
40 L ÷ 500 km × 100
- km per litre
- 12.5
- Per km
- 19.0c
- Per 100 km
- $19
No price.
Against the label. The label is L/100km. Yours is : . These bands are an Estimate from AAA road tests.
Why so high?
Road test.
Price. Default price: National average for the week ending 27 September 2026, cents per litre including GST. Source: Australian Institute of Petroleum, Weekly Petrol Prices Report. Retail data supplied to AIP by MotorMouth. AIP weekly reports.
Going somewhere? Plan a trip with this figure.8
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How we calculated this
Fill the tank to the top
Fill until the pump clicks off, then zero the trip meter or note the odometer.
Drive as normal
Use most of the tank on your usual mix of driving.
Fill to the top again and note two numbers
The litres it took, and the km since the last fill.
40 L over 500 km
Litres per 100 km
Litres ÷ km × 100. This is the same unit as the label on your car.
8 L/100km, or 12.5 km per litre
Cost per km
Litres × price ÷ km, when there is a price.
19.0c
This is the full-to-full method from the US Department of Energy's fueleconomy.gov (US units, same method). CarsGuide has a worked example in L/100km.
Default price: capital-city or national average for the week ending 27 September 2026, cents per litre including GST. Source: Australian Institute of Petroleum, Weekly Petrol Prices Report (diesel: Weekly Diesel Prices Report). Retail data supplied to AIP by MotorMouth. AIP weekly prices reports.
| Band | Most cars | Hybrids | Checked |
|---|---|---|---|
| Normal | up to +11% | up to +15% | Estimate |
| Higher than most | +11% to +19% | +15% to +23% | Estimate |
| Well above | over +19% | over +23% | Estimate |
AAA drives carefully to fixed rules, so a figure above these bands is not proof of a fault. A figure below the label counts as normal.
Sources
- Green Vehicle Guide: vehicle search (L/100km for each variant)
- Green Vehicle Guide: fuel consumption label (ADR 81/02 and 81/03)
- Green Vehicle Guide: real world emissions
- Green Vehicle Guide: tips to reduce your emissions
- AAA: Real-World Testing Program results
- AAA: 76% of cars tested use more fuel than advertised (18 Jun 2026)
- FCAI: new vehicle market remains resilient (6 Jan 2026)
- CarExpert: VFACTS 2025 full year (6 Jan 2026)
- fueleconomy.gov: Odometer Method (US Department of Energy)
- CarsGuide: how to calculate fuel consumption (28 Dec 2022)
- Australian Institute of Petroleum: Weekly Prices Reports
- Australian Institute of Petroleum: Weekly Petrol Prices Report, week ending 27 September 2026 (retail data supplied by MotorMouth)
- Australian Institute of Petroleum: Weekly Diesel Prices Report, week ending 27 September 2026 (retail data supplied by MotorMouth)
Questions
Why is one fill-up only a rough figure?
A pump can click off at a slightly different level each time. A trip meter also rounds. Add up the km and the litres over several fills for a steadier figure.
Why is my figure higher than the label?
The label is a lab test. On the road, the 162 cars in the AAA Real-World Testing Program used 6.3% more than their label on average. That average is an Estimate: our sum of AAA's published results. AAA drives carefully, so your own driving may use more. From 1 July 2026, new models are labelled under the WLTP test (ADR 81/03). It is built to be closer to real driving. Every new vehicle follows from 1 July 2028. Pick your car above to see where your figure sits.
What is the difference between L/100km and km/L?
L/100km is the litres used to drive 100 km, so lower is better. km/L is how far one litre takes you, so higher is better. To swap one for the other, divide 100 by it. The example fill is 8 L/100km, or 12.5 km per litre.