The small cars that consume the most fuel

Small passenger cars like hatchbacks and sedans often consume less fuel than SUVs and utes, but new test data claims that some have a greater fuel consumption than their advertised numbers suggest.

The results come from the Australian Automotive Association’s (AAA) real-world fuel-efficiency testing program, which is funded by the Australian Government. It started in 2023 and will run through to 2027 and will evaluate 200 popular vehicles during that time.

At present, the AAA has tested 86 vehicles across six rounds.

In these rounds, the peak motoring body has assessed 16 small cars, with the latest batch encompassing some of the most popular models on the Australian market.

Out of the 16 pint-sized vehicles assessed in the program, the 2024 Mazda 2 light hatchback performed the worst in the latest round, consuming 35 per cent more fuel during real-world testing at 6.8 litres per 100 kilometres in comparison to the AAA's lab-tested 5.0L/100km rating.

A 2021 Mazda 3 fared slightly better, recording a 3 per cent discrepancy between its real-world consumption of 6.4L/100km and its lab-tested fuel-efficiency rating of 6.2L/100km.

“We welcome any new additional testing over and above the mandatory ADR testing applicable to all vehicles where it intends to inform and equip consumers with more accurate results,” a Mazda spokesperson told Drive.

“However, it is important to note that individual driver profiles will invariably differ to those results achieved,” they added.

The Suzuki Swift hatch wasn't too far behind, with a 2024 hybrid and 2023 petrol variant recording a 31 per cent variance between the real-world test (5.2L/100km and 6.3L/100km, respectively) and lab-tested figures of 4.0L/100km and 4.8L/100km.

A Suzuki spokesperson said the added equipment weight during the AAA's testing “has a bigger impact on the fuel-efficiency of lighter vehicles”.

“In AAA's tests, measurements are taken with equipment weighing about 300kg installed on the vehicle in addition to the driver, making the total weight of the vehicle heavier than in certification tests at laboratories,” they told Drive.

“If the same equipment is used in AAA's tests for all vehicles, the proportion of total weight increase on the vehicles will be larger in lighter vehicles compared to larger and heavier vehicles, and the impact on fuel-efficiency values will also be relatively greater for lighter vehicles.

“[This results] in a larger discrepancy from the values of the certification tests,” a Suzuki spokesperson added.

Suzuki also pointed towards there being differences in conditions between lab tests and driving on actual roads, specifically factors such as individual driving patterns, air-conditioning usage, road gradients, wind, temperature and weight.

“The test conditions of the certification test and those of AAA tests are fundamentally different. It is not appropriate to comment on the fuel-efficiency performance of any particular vehicle or manufacturer solely based on the gap of fuel-efficiency test results,” they added.

A 2024 MG 5 sedan and 2023 MG 3 hatch were also among the thirstiest small vehicles tested by the AAA across six rounds, consuming 21 per cent and 19 per cent more fuel, respectively (at 8.0L/100km and 7.9L/100km) than their fuel-efficiency ratings of 6.6L/100km and 6.7L/100km.

Among the small cars tested across the AAA’s six rounds, the Toyota Corolla performed the best, with a 2022 Corolla drinking 3 per cent more fuel in real-world environments (6.2L/100km) than in lab-controlled conditions (6.0L/100km).

Meanwhile, a 2024 Toyota Corolla Hybrid showed no fuel consumption discrepancy, with the AAA achieving the car maker’s claimed 4.2L/100km efficiency rating during the sixth round.

Popular consumer favourites like the Hyundai i30 recorded a real-life fuel-efficiency variance of 1 per cent for the 2023 variant (7.5L/100km) and 11 per cent for the 2024 model when compared to the hatch’s lab-tested ratings of 7.4L/100km and 6.1L/100km, respectively.

According to the AAA's data, a 2024 Kia Cerato – now replaced by the K4 in Australia – drank 8 per cent more fuel in real-world conditions at 7.3L/100km as opposed to its advertised 6.8L/100km.

However, its 2023 predecessor consumed 10 per cent less fuel on local roads at 6.7L/100km than its 7.4L/100km sticker efficiency rating.

At the luxury end, a 2024 Audi A3 Sportback achieved a real-world result of 8.1L/100km, a 21 per cent increase in comparison to its claimed 6.7L/100km rating.

A 2023 Mini Cooper hatch drank 6 per cent more fuel on local roads (6.3L/100km) than its lab-tested 5.9L/100km figure.

"The fuel consumption figure for the Mini Cooper is calculated based on standardised and controlled testing as per the ADR 81/02 Fuel Consumption Labelling for Light Vehicles," a Mini Australia spokesperson told Drive.

Given the varying range of discrepancies between the lab-tested and real-life fuel consumption data, Michael Bradley, AAA's Managing Director, said the program highlights the importance of educating buyers.

The AAA said its testing is performed on roads around Geelong – a city approximately 76km south-west of Melbourne – with the program using “strict protocols” to achieve repeatable results and mitigate external factors like driving style and traffic flows.

Still, the peak motoring body said the final fuel consumption results offer a variability “of less than 2.5 per cent”.

“These results again show real-world testing is needed to help consumers and fleet buyers avoid buying a vehicle that produces more emissions and higher running costs than advertised.

“While some cars perform as per the information at point of sale, our program is revealing that many, if not most, do not,” Bradley said in a media statement.

However, some brands alongside the Federal Chamber of Automotive Industries (FCAI), which represents most manufacturers in Australia, previously expressed its hesitancy when it comes to the AAA’s fuel-efficiency program given how consumption can fluctuate depending on a range of external factors.

“The FCAI believes that the current government-funded real-world testing program presents too many variables and can have the risk of confusing consumers rather than providing clarity,” Tony Weber, the Chief Executive of the FCAI, said in a media statement.

Toyota and Hyundai Australia declined to comment. Drive has contacted Kia, Audi and MG and will update this story if a response is received.

Ethan Cardinal graduated with a Journalism degree in 2020 from La Trobe University and has been working in the fashion industry as a freelance writer prior to joining Drive in 2023. Ethan greatly enjoys investigating and reporting on the cross sections between automotive, lifestyle and culture. Ethan relishes the opportunity to explore how deep cars are intertwined within different industries and how they could affect both casual readers and car enthusiasts.

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