Compare the2022 Audi A3VS 2021 Mercedes C-Class Sedan

Both the A3 and C-Class Sedan have child safety locks to prevent children from opening the rear doors. The A3 has power child safety locks, allowing the driver to activate and deactivate them from the driver's seat and to know when they're engaged. The C-Class Sedan’s child locks have to be individually engaged at each rear door with a manual switch. The driver can’t know the status of the locks without opening the doors and checking them.

The A3 has a standard Secondary Collision Brake Assist, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The C-Class Sedan doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.

The A3’s standard lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane and gently nudges the vehicle back towards its lane. A lane departure warning system costs extra on the C-Class Sedan.

Both the A3 and the C-Class Sedan have standard driver and passenger frontal airbags, front and rear side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras, available all wheel drive, blind spot warning systems, rear parking sensors and rear cross-path warning.

The A3’s corrosion warranty is 7 years longer than the C-Class Sedan’s (12 vs. 5 years).

The Audi A3’s engine uses a cast iron block for durability, while the C-Class Sedan’s engine uses an aluminum block. Aluminum engine blocks are much more prone to warp and crack at high temperatures than cast iron.

A reliable vehicle saves its owner time, money and trouble. Nobody wants to be stranded or have to be without a vehicle while it’s being repaired. Consumer Reports rates the A3’s reliability 20 points higher than the C-Class Sedan.

From surveys of all its subscribers, Consumer Reports’ January 2021 Auto Issue reports that Audi vehicles are more reliable than Mercedes vehicles. Consumer Reports ranks Audi 6 places higher in reliability than Mercedes.

On the EPA test cycle the A3 gets better mileage than the C-Class Sedan:

Regenerative brakes improve the A3’s fuel efficiency by converting inertia back into energy instead of wasting it. The C-Class Sedan doesn’t offer a regenerative braking system.

To lower fuel costs and make buying fuel easier, the Audi A3 uses regular unleaded gasoline (premium recommended for maximum performance). The C-Class Sedan requires premium, which can cost 20 to 55 cents more per gallon.

In its Green Vehicle Guide, the U.S. Environmental Protection Agency (EPA) rates the Audi A3 higher (7 out of 10) than the Mercedes C-Class Sedan (6). This means the A3 produces up to 1.1 pounds less smog-producing pollutants than the C-Class Sedan every 15,000 miles.

The A3 offers a standard sequential manual gearbox (SMG). With no clutch pedal to worry about and a fully automatic mode, an SMG is much more efficient than a conventional automatic but just as easy to drive. The C-Class Sedan doesn’t offer an SMG or a conventional manual transmission.

The A3’s standard tires provide better handling because they have a lower 45 series profile (height to width ratio) that provides a stiffer sidewall than the C-Class Sedan’s 50 series tires.

The A3 has a standard space-saver spare tire so you can replace a flat tire and drive to have the flat repaired or replaced. A spare tire isn’t available on the C-Class Sedan; it requires you to depend on its run-flat tires, which limits mileage and speed before they are repaired. If a run-flat is damaged beyond repair by a road hazard your vehicle will have to be towed. Some tire options on the C-Class Sedan don’t have a run-flat feature, either.

The A3 offers an optional driver-adjustable suspension system. It allows the driver to choose between an extra-supple ride, reducing fatigue on long trips, or a sport setting, which allows maximum control for tricky roads. The C-Class Sedan’s suspension doesn’t offer adjustable shock absorbers.

The A3 is 7.6 inches shorter than the C-Class Sedan, making the A3 easier to handle, maneuver and park in tight spaces.

The design of the Audi A3 amounts to more than styling. The A3 has an aerodynamic coefficient of drag of .27 Cd (optional .26 Cd with Quattro). That is lower than the C-Class Sedan (.3) and many sports cars. A more efficient exterior helps keep the interior quieter and helps the A3 get better fuel mileage.

The A3 has a 3500 lbs. towing capacity. The C-Class Sedan has no towing capacity.

J.D. Power and Associates surveys of service recipients show that Audi service is better than Mercedes. J.D. Power ranks Audi 8th in service department satisfaction (above the industry average). With a 16% lower rating, Mercedes is ranked 18th.

In poor weather, headlights can lose their effectiveness as grime builds up on their lenses. This can reduce visibility without the driver realizing. The A3 Prestige has standard headlight washers to keep headlight output high. The C-Class Sedan doesn’t offer headlight washers.

Consumer Reports® recommends the Audi A3, based on reliability, safety and performance.