Audi A4 (2021) Review — Reliability, Running Costs & Specs
Full UK review of the 2021 Audi A4. Covers reliability, MPG, insurance groups, ownership costs, common issues and verdict.
38–55 mpg
Combined MPG
24–38
Insurance Group
£190/yr
Road Tax/yr
7.8–9.3 seconds
0–60 mph
Full Specifications
Overview
The 2021 Audi A4 is part of the B9 generation, launched in 2015 and facelifted in 2019. By 2021, all models featured mild hybrid assistance on petrol and diesel variants, 12V systems that aid efficiency during light acceleration and regenerate during braking. The interior was updated with Audi's latest MMI infotainment and Virtual Cockpit digital dials as standard on most trims.
What's the Audi A4 Like to Drive?
The A4 prioritises refinement over sportiness. The suspension isolates road noise exceptionally well, the cabin is whisper-quiet at motorway speeds, and the S tronic gearbox shifts almost imperceptibly in comfort mode. Base models are front-wheel drive; quattro all-wheel drive is available on higher-power engines and adds meaningful traction in UK winter conditions.
Highlights
- Best-in-class interior refinement and materials quality
- Virtual Cockpit digital dials standard — clear and configurable
- Quiet, composed motorway cruiser
- Quattro AWD available on higher trims for year-round traction
- Mild hybrid system reduces fuel consumption in urban driving
Which Engine to Choose?
For most buyers, the 40 TDI diesel (204ps, 400Nm) is the sweet spot. It delivers strong real-world economy and effortless performance. The 35 TFSI petrol (150ps) is better suited to lower-mileage urban drivers who want lower upfront cost. Avoid the higher-performance S4 unless insurance costs and fuel bills are not a concern.
Reliability
The B9 Audi A4 (2016–2023) has a mixed reliability record. Owner surveys from What Car? and JD Power have placed it slightly below the BMW 3 Series in reliability rankings. The S tronic DSG gearbox has been the most reported source of issues. The mild hybrid 12V system on later models (2020+) has been more dependable.
Known Issues to Watch
Estimated Annual Ownership Costs
Estimates based on average UK driver doing ~10,000 miles/year.
Verdict
The 2021 Audi A4 is a compelling executive saloon with a genuinely premium interior, excellent technology, and a refined driving experience. It falls slightly short of the BMW 3 Series on driving engagement and reliability data, but if interior quality and tech matter most, it's a very strong choice. Buy from a full Audi service history seller and have the S tronic gearbox checked on any test drive.
Frequently Asked Questions
Is the Audi A4 reliable?
The B9 A4 has an average reliability record compared to rivals. The S tronic DSG gearbox is the most common source of issues. Choose examples with full Audi service history and check the gearbox carefully on any test drive.
What MPG does a 2021 Audi A4 return?
The 2021 Audi A4 returns 38–55 mpg depending on engine. The 35 TFSI petrol returns around 38–44 mpg in real use, while the 40 TDI diesel returns 45–53 mpg on a mixed run.
Which is better — Audi A4 or BMW 3 Series?
For interior quality and refinement, the Audi A4 edges ahead. For driving enjoyment, reliability, and boot space, the BMW 3 Series has the edge. See our full head-to-head comparison for a detailed breakdown.
What insurance group is a 2021 Audi A4?
The 2021 Audi A4 sits in insurance groups 24–38 depending on engine and trim. The 35 TFSI base petrol sits around group 24–28, while the 40 TDI quattro S line sits around group 34–38.
How do I check the history of a used Audi A4?
Use MOTR to check the full MOT history, mileage at each test, and tax status for any UK Audi A4. Just enter the registration number for a full free check.