Your Guide to Understanding Fuel Efficiency & Ratings in Canada

What is good fuel efficiency for a car? How is fuel efficiency measured in Canada? What impacts fuel consumption — and how can you drive more efficiently?

Great questions to ask, considering Canada ranked last for average fuel efficiency and contributes the most carbon emissions among driving nations.


Here’s your guide to understanding fuel efficiency for internal combustion engine (ICE) cars so you can burn less gas, saving you money and reducing your tailpipe emissions.

What is fuel efficiency?

Fuel efficiency is the measure of how much gas (or diesel) fuel an ICE vehicle uses to travel a given distance. In Canada, fuel efficiency is measured as liters of gas used to drive 100 kilometers, or L/100km. A lower figure is more fuel efficient, because it represents less fuel used across the same number of miles.

While fuel efficiency is impacted by countless variables including individual driving style and environmental conditions, these average numbers help shoppers compare efficiency between models. It’s easy to understand that a car capable of 5 L/100km is more efficient than one rated for 8 L/100km.

Fuel-sipping ICE cars and electrified models can be as efficient as 3 L/100km. Most cars and small to medium SUVs can achieve an efficiency of around 5 to 11 L/100km. Larger SUVs, trucks, and sports cars fall into the least-efficient category, with fuel economy ratings in the 15-20+ L/100km range.

Good fuel efficiency is a subjective and relative measure, but when it comes to gas-only (non-electrified) cars for sale in Canada, the Mitsubishi Mirage tops the list. With a combined fuel efficiency rating of 6 L/100km, the Mirage’s 1.2-litre 3-cylinder engine is responsive and sporty yet sips fuel to reduce costs and tailpipe emissions.

What impacts fuel economy?

The most influential factor, after the vehicle’s powertrain, is the variable behind the wheel. Driving style can turn an economy car into a gas-guzzler or vice versa. Stomp on the gas pedal, race through the streets, and wait until the last second to start slowing down and you’re going to burn a whole lot more fuel.

Traffic is also a consideration. Fuel efficiency is better on the highway when cruising at constant speed. On city streets and in heavier traffic, more fuel is used because of how often the car has to accelerate. Acceleration requires additional power from the engine, which means squirting more fuel into the cylinders to rev higher.

External temperatures and weather conditions also impact fuel economy. Extreme cold and heat will make an engine work harder and run less efficiently. Even variations in air temperature and density, like driving up into the mountains, can impact fuel economy.

Aerodynamics; the ability of a car to slice through the air, also affects fuel efficiency. Sleek, smooth designs move through the air more easily than big, boxy ones. Some cars even have active aero features that open and close flaps underneath the car and inside the grille to adjust how air flows around the car at varying speeds to optimize for fuel economy.

Vehicle condition and maintenance will also have an influence on fuel economy. An engine with thick, dirty oil and clogged filters will struggle to run as efficiently as one with fresh oil, filters, spark plugs, and other belts, fluids, and worn items properly maintained and replaced.

Tires play a role due to how they contact the road. Eco tires optimize fuel efficiency by reducing rolling resistance to make it easy to rotate the wheel. Performance-minded tires will be stickier to push harder against the road for higher traction, acceleration, and speed, but that added stickiness works against fuel efficiency.

Onboard features can also decrease fuel efficiency. Engaging selectable four/all-wheel-drive adds drivetrain resistance that requires additional power from the engine to overcome. ICE cars’ air conditioning systems run off the engine, so turning on the A/C costs extra fuel, too.

All these factors can improve or decrease fuel economy, but the most fundamental element determining fuel efficiency is weight.

How does weight affect fuel efficiency?

The heavier a car is, the harder it is to move. That means the engine works harder, burning more fuel than it would for a lighter vehicle. More weight means it’s harder to rotate the wheels under the car, so accelerating and cruising both require more fuel to counteract the opposing forces of inertia (to get scientific).

Saving money and the planet

Better fuel efficiency benefits the planet because it means less carbon and greenhouse gas emissions from the tailpipe. Using less fuel also means buying less fuel, so fuel efficiency decreases gasoline demand. Consider the environmental impact of the entire supply chain that brings gasoline from the depths of the Earth to your gas pump. Not only will less oil drilling help the planet, so will fewer big trucks on the road hauling fuel tankers.

Using less fuel means using less of Earth’s resources and reducing the amount of dirty, toxic, and unhealthy chemicals our cars emit into the atmosphere.

Of course, burning less gas will also translate to a higher balance in your bank account. Often, the cost of moving from an old, inefficient car into a new, fuel-efficient model or electrified option is balanced out by spending less at the pump. Yet even with a standard ICE car, you can take various steps to improve your fuel efficiency, reducing fuel consumption and environmental impact, meaning every driver can work towards a greener future.

How you can improve fuel efficiency

Adopting efficiency-minded driving habits is a key factor in maximizing fuel economy. For instance, avoiding rapid acceleration and braking can significantly reduce fuel consumption, as these actions require more energy to be produced by the engine.

Planning your trips to combine errands minimizes unnecessary travel, further cutting down on fuel usage. At higher speeds, keeping windows closed to reduce drag, which can otherwise make your engine work harder, also helps. So does removing external accessories like roof racks, which cause aerodynamic drag that decreases fuel efficiency.


The air conditioner runs off the engine, so being mindful of A/C use helps save gas. Keeping the A/C system maintained with refrigerant and clean filters also helps. Cars with a sunroof have an added bonus — pop the roof open when you start the car so all the hot air escapes up and out quickly, letting the cool A/C air take its place sooner.


Limiting idling time saves fuel that would otherwise be wasted, and using cruise control on the highway helps maintain a steady speed, improving fuel efficiency. Additionally, reducing unnecessary weight in your vehicle — it’s about time you clean out the trunk — and planning efficient routes can make a noticeable difference in how much fuel your vehicle consumes.


Regular vehicle maintenance also plays a crucial role in ensuring optimal fuel efficiency. Properly inflated tires reduce rolling resistance, and visiting the service center for regular maintenance keeps your engine running smoothly. Using the recommended grade of motor oil for your vehicle can also enhance engine performance and fuel economy.

Fuel-saving technologies

Sustainably minded automakers are also deploying high-tech features to make their gasoline cars run more efficiently. For instance, Mitsubishi offers Super All-Wheel Control (S-AWC) which includes drive modes for various scenarios, including Sport, Snow, Mud, Power, and — you guessed it — Eco. Eco mode adjusts the engine, transmission, and all-wheel-drive system’s operation for maximum efficiency to get the most kilometers out of every litre of gas.

Computer control modules can do plenty to manage a car’s systems to manage fuel efficiency smartly. Automakers also invest in research and innovation to develop more advanced tires, construction materials, aerodynamic designs, and other inventions that reduce the work needed to propel a vehicle forward.

Engine technology like turbocharging that allows smaller engines to produce more power, direct fuel injection for more efficient combustion, and start-stop systems that reduce idle time also make a big difference in fuel economy. Hybrid technologies, combining a gasoline engine with an electric motor, offer significant fuel savings by enabling electric-only driving modes and regenerative braking. Together, these strategies and technologies provide drivers with a multitude of ways to improve fuel efficiency, save money, and reduce their environmental impact.

Hybrids and EVs

Hybrids and plug-in hybrids (PHEVs) add a battery and electric motor to assist the gas engine. This provides gas-free miles and more efficient miles even when using the gas engine since it doesn’t have to work as hard. Plug-ins can top up from the grid in addition to being charged by the engine and regenerative braking. They can get as low as about 3 L/km (78 mpg) or about 4-6 L/100km (40-60 mpg) in most cases.

EVs ditch the gasoline altogether. Efficiency for an EV is measured in Le/100km (gasoline litres equivalent per 100 km), a measurement that relates electric efficiency to gasoline efficiency for easier comparison. EVs can easily achieve 2 Le/10km (100+ mpg equivalent) and emit no tailpipe emissions. The cost and environmental impact of electricity generation and delivery to your charger also influence the total efficiency and eco-friendliness of an EV, but having such an efficient powertrain tips the balance in their favor.

The most fuel-efficient gas cars

You don’t have to go right for the electrified models to prioritize fuel efficiency. Ultra-efficient internal combustion engines can eke out more kilometers per liter than ever before while still offering the engagement and flexibility of a gas powertrain. Check out the 2024 Mitsubishi Mirage, which is the most efficient gas car on sale in Canada and one of the least expensive to buy.