What Are the Key Differences Between Audi A3 and Audi A4?

How Does Size and Styling Compare?

One of the most noticeable differences between the Audi A3 and the Audi A4 is their size. The A4 Saloon is over 40cm longer than the A3 Sportback, though the gap narrows to about 26cm when comparing the A3 Saloon with the A4. Size isn’t everything, though; the A4 has been around since 2015, receiving an update in 2019, whereas the A3 was introduced in 2020. This means the A3 feels more modern in terms of design and technology.

Both models come in various trims like the cost-effective Technik through to the sporty S line and the top-of-the-range Vorsprung. For performance enthusiasts, there are high-powered versions like the S3, S4, RS3, and RS4.

Audi A3

A gray Audi A3 Sportback car driving on a road with a field and trees in the background. The car has a sporty design with large alloy wheels and a prominent grille. The license plate on the car is LJV 360.

Audi A4

A blue Audi A4 sedan driving on a road with a field and trees in the background. The car has a sporty design with large alloy wheels and a prominent grille. The license plate on the car is JJF 500.

Which Interior and Tech Features Shine?

Step inside these cars, and the differences continue. The A3 boasts a cutting-edge dashboard with a central touchscreen infotainment system that feels modern and high-tech. The A4, while still luxurious, feels a bit more traditional with a smaller screen on top of the dashboard.

Both cars have similar tech features, including built-in sat nav, Apple CarPlay, and Android Auto. The A3’s system is touchscreen-controlled, whereas the A4 employs a click wheel by the gear lever. Both are user-friendly, though the A3’s system can be slow to load upon startup.

Standard features include air conditioning, cruise control, parking sensors, and a digital driver’s display that you can customise to show various bits of information.

 

Audi A3

The interior of an Audi A3 Sportback car. The dashboard features a large touchscreen display, and the seats are upholstered in black leather. The steering wheel has multiple buttons for controls, and the center console includes a gear selector and other buttons.

Audi A4

The interior of an Audi A4 car. The dashboard features a large touchscreen display, and the seats are upholstered in black leather. The steering wheel has multiple buttons for controls, and the center console includes a gear selector and other buttons.

 

How Practical Are the Boot Space and Seating?

Practicality is another area where these cars differ. Most Audi A3 hatchbacks offer 380 litres of boot space, while the saloon version provides 425 litres, but the saloon’s smaller boot opening can make loading larger items tricky. In contrast, the A4 Saloon has a more generous 480-litre boot, easier to load with its flat and square shape. If you need even more space, the A4 Avant estate offers a substantial 495 litres.

Both cars provide ample space in the front seats, and there’s enough room in the back for two tall adults. However, the A4 offers more legroom and a middle back seat that’s suitable for short journeys. Older children or taller passengers will find the A4 more comfortable.

 

Audi A3

The open trunk of an Audi A3 Sportback car. The trunk is empty and has a spacious interior with a flat load floor. The rear taillights are visible on either side of the trunk opening. The tailgate is open and propped up.

Audi A4

The open trunk of an Audi A4 car. The trunk is empty and has a spacious interior with a flat load floor. The rear taillights are visible on either side of the trunk opening. The tailgate is open and propped up.

 

Which Car is Best to Drive?

The Audi A3 is a versatile all-rounder, comfortable on city streets, country roads, and motorways alike. Light steering makes urban driving a breeze, and models with 150bhp or more benefit from enhanced rear suspension for a smoother ride.

The A4, being larger and heavier, doesn’t feel as agile but provides a satisfying driving experience. Its steering is precise, there’s minimal body lean in corners, and it’s a quiet and comfortable cruiser on motorways.

Both models offer four-wheel drive options (Quattro) for added stability on slippery roads. There’s a wide range of petrol and diesel engines available, with the A3 also offering a plug-in hybrid option.

Audi A3

A gray Audi A3 Sportback car driving on a road with trees and a field in the background. The car is in motion, and the rear of the car is visible, showing the taillights, rear bumper, and license plate. The license plate on the car is LJV 360.

Audi A4

A blue Audi A4 sedan driving on a road with a field in the background. The car is in motion, and the rear of the car is visible, showing the taillights, rear bumper, and license plate. The license plate on the car is JJF 500.

 

 

Which Car Costs Less to Own?

When it comes to running costs, the A3 generally edges out the A4. With petrol engines, the A3 averages 37-55mpg, while the A4 delivers 35-46mpg. Diesel engines can see the A3 reaching up to 65mpg and the A4 up to 60mpg. The plug-in hybrid A3 is the most efficient, with an official average of 256mpg and an electric-only range of about 40 miles.

Both cars have relatively low car tax, particularly the plug-in hybrid A3s.

 

Audi A3

A gray Audi A3 Sportback car parked in a field with a sunset in the background. The car has a sporty design with large alloy wheels and a prominent grille. The license plate on the car is LJV 360.

Audi A4

A blue Audi A4 sedan parked on a hilltop with a scenic landscape in the background. The car has a sporty design with large alloy wheels and a prominent grille. The license plate on the car is JJF 500.

 

How Safe and Reliable Are They?

Safety is a strong suit for both models, each earning a five-star rating from Euro NCAP. Standard safety features include automatic emergency braking and cruise control with a speed limiter. The A3 additionally comes with lane-departure warning and lane-keeping assist.

However, it’s worth noting that Audi ranked 22nd out of 24 car manufacturers in the J.D. Power 2019 UK Vehicle Dependability Study, so while these cars are high-quality, their reliability might not be as stellar as you’d hope.

What Are the Dimensions?

Audi A3

  • Length: 4343mm
  • Width: 1984mm (including door mirrors)
  • Height: 1430mm
  • Boot space: 380 litres

Audi A4

  • Length: 4762mm
  • Width: 2022mm (including door mirrors)
  • Height: 1428mm
  • Boot space: 480 litresA side-by-side comparison of two cars, an Audi A3 and an Audi A4. The cars are shown from above, with their dimensions labeled. The Audi A3 is gray, and the Audi A4 is blue. The dimensions compared are length, width (including mirrors), height, and boot space.

Verdict

Both the A3 and the A4 are excellent vehicles, offering a premium feel, good driving dynamics, and practical features. However, if we had to pick a winner, it would be the Audi A3. It’s spacious enough for most needs, feels more up-to-date, is more fuel-efficient, and offers a rewarding driving experience—all while costing less to buy and run.

Final Thoughts

Choosing between the Audi A3 and the Audi A4 ultimately depends on your specific needs and preferences. The A3 offers modern design, efficiency, and practicality, making it an excellent choice for most drivers. The A4, with its additional space and comfort, may be better suited for those who need a bit more room or frequently drive longer distances.

Ready to make a decision? Explore our extensive range of used Audi A4 and Audi A3 models at MOTORS and find the perfect car for you.

For more detailed advice and guidance on buying used cars, check out our safe buying advice and buying a used car checklist. Explore our comprehensive guides to ensure you get the best deal possible.