The 2021 Audi A4 delivers exceptional luxury sedan performance with its refined 261-horsepower turbocharged 2.0-liter engine that achieves 27 mpg combined fuel economy. Originally starting at $41,945 for the Premium trim, this German-engineered masterpiece now commands $18,000 to $32,000 in today's used market. The 2021 model year introduced significant technological advancement including 12-volt mild hybrid system, standard quattro all-wheel drive, and enhanced safety features that earned IIHS Top Safety Pick recognition. Consumer testing shows 28.7 mpg real-world fuel economy with excellent 0-60 mph acceleration in 4.8 seconds. With 273 lb-ft of torque available from just 1,600 RPM and Audi's advanced Virtual Cockpit technology, the A4 combines luxury refinement with engaging driving dynamics that define modern German automotive excellence.

What makes the 2021 Audi A4 exceptional in its class?

The 2021 Audi A4 represents evolutionary perfection of Audi's B9 generation platform. This model year brought game-changing mild hybrid technology while maintaining the build quality that earned industry acclaim.

Car and Driver praised the A4 as "easy to like and hard to fault" with its handsome styling, excellent build quality, and comprehensive feature list. This wasn't just automotive journalism hyperbole. The 2021 A4 delivered measurable improvements across all performance metrics.

Revolutionary mild hybrid integration

The most significant upgrade was 12-volt mild hybrid system integration that enhanced both performance and efficiency. Advanced electrical architecture reduced traditional turbo lag while improving fuel economy figures.

Major 2021 technological enhancements:

• 12-volt mild hybrid system standard across all models
• Enhanced quattro all-wheel drive system with improved torque distribution
• Upgraded infotainment with wireless Apple CarPlay integration
• Advanced driver assistance systems with improved sensor accuracy
• Refined suspension tuning balancing comfort and performance

The cabin received meaningful technology updates including improved materials and enhanced connectivity features. Every surface demonstrates Audi's commitment to luxury craftsmanship that rivals more expensive German competitors.

Actionable takeaways:

• 2021 offers peak mild hybrid technology integration
• Enhanced connectivity systems eliminate aftermarket upgrades
• Improved efficiency addresses environmental concerns effectively

How much does a 2021 Audi A4 cost in today's market?

The 2021 A4 pricing structure offered distinct trim levels targeting different luxury preferences and performance requirements across multiple markets.

Current used market analysis

Based on July 2025 market data, the 2021 A4 offers exceptional value proposition in today's used luxury market. Depreciation has created significant opportunities for buyers seeking German luxury at accessible prices.

Market factors affecting current pricing:

• Mileage premium: Low-mileage examples under 30,000 miles command 25-30% premium
• Trim optimization: Premium Plus 45 TFSI offers best feature-to-price ratio
• Condition multiplier: Excellent condition certified pre-owned adds $4,000-5,000 value
• Service documentation: Complete maintenance records increase resale value 20-25%

The optimal purchase target appears to be Premium Plus 45 TFSI models with 40,000-60,000 miles, offering advanced technology and maximum performance without Prestige pricing premiums.

Regional market variations:

• Northern markets: Quattro models command $3,000-4,000 premium due to weather demands
• Southern regions: Base models offer better value proposition
• International markets: Vietnam pricing reflects import duties and luxury taxes

What engine technology powers the 2021 A4's performance?

Every 2021 A4 features Audi's sophisticated 2.0-liter TFSI turbocharged four-cylinder engine available in two distinct power configurations with revolutionary mild hybrid integration.

Advanced mild hybrid technology breakdown

The 12-volt mild hybrid system provides precision electric assistance that optimizes combustion efficiency across all operating conditions. Peak torque availability from just 1,450 RPM makes both A4 configurations feel incredibly responsive during real-world driving scenarios.

Key technological innovations:

• Belt-starter generator enables seamless start-stop functionality
• Electric torque fill eliminates traditional turbo lag completely
• Regenerative braking recovers energy during deceleration phases
• Advanced engine management optimizes fuel delivery precisely

This engine produces 100.5-130.5 horsepower per liter depending on configuration, demonstrating Audi's engineering excellence in extracting maximum performance from compact displacement.

Performance characteristics analysis:

• Immediate throttle response eliminates traditional turbo lag completely
• Linear power delivery throughout the rev range enhances drivability
• Refined operation with minimal noise, vibration, harshness intrusion
• Strong mid-range torque ideal for highway overtaking maneuvers

Actionable takeaways:

• Mild hybrid technology significantly improves efficiency without performance compromise
• Premium fuel requirement ensures optimal performance and engine longevity
• Regular maintenance every 10,000 miles maintains peak reliability standards

How does the 2021 A4's transmission perform?

The 2021 A4 came standard with Audi's advanced 7-speed S tronic dual-clutch automatic transmission across all trim levels. This sophisticated system delivers rapid shifts and responsive performance characteristics.

Dual-clutch technology advantages

The S tronic system eliminates power interruption typical of conventional automatics through innovative engineering. Two separate clutches manage odd and even gears independently, enabling instantaneous gear changes under all driving conditions.

Transmission performance benefits:

• Lightning-fast gear changes during acceleration phases
• Manual mode with steering wheel paddle shifters for driver control
• Adaptive shift patterns automatically adjust to individual driving styles
• Launch control functionality for optimal standing start acceleration
• Smooth operation during city driving eliminates jerky behavior

Drivetrain configuration excellence

Quattro all-wheel drive comes standard across all 2021 A4 models, eliminating the choice between drive systems. The quattro system provides superior traction and enhanced driving dynamics year-round.

Quattro system operational advantages:

• 40/60 front/rear torque distribution under normal driving conditions
• Instant adjustment to changing road surface conditions automatically
• Enhanced cornering stability through intelligent torque vectoring
• Superior capability during adverse weather conditions significantly

The drive select system allows comprehensive customization of throttle response, transmission behavior, and steering weight through multiple selectable driving modes.

Available driving mode configurations:

• Comfort: Optimized for daily driving comfort and maximum fuel economy
• Auto: Automatically adjusts all parameters to match driving conditions
• Dynamic: Sporty settings for enthusiastic driving experiences
• Individual: Custom configuration of all vehicle parameters precisely

Actionable takeaways:

• Dual-clutch technology provides sports car-like shift responsiveness
• Standard quattro all-wheel drive eliminates weather-related concerns
• Drive select customization significantly enhances overall driving experience

What technology features define the 2021 A4?

The 2021 A4's technology systems represented cutting-edge automotive capability that remains competitive against newer luxury sedans today. Audi's MMI interface provides intuitive control without overwhelming complexity.

Infotainment and connectivity systems

Standard equipment includes a crisp 10.1-inch MMI touchscreen display with comprehensive smartphone integration. Wireless Apple CarPlay came standard across all trim levels, eliminating expensive option package requirements.

Core technology feature lineup:

• MMI touch infotainment with high-resolution color touchscreen display
• Wireless Apple CarPlay and Android Auto integration standard equipment
• Bluetooth connectivity with hands-free calling and audio streaming
• SiriusXM satellite radio with complimentary trial subscription
• Dual-zone automatic climate control with precision temperature management

Virtual Cockpit system implementation

The available 12.3-inch Virtual Cockpit replaces traditional analog gauges with a fully customizable digital display system. Drivers can configure screen layouts to emphasize navigation, audio, or performance information dynamically.

Virtual Cockpit advanced capabilities:

• Full-screen Google Earth navigation mapping with real-time traffic
• Customizable performance and efficiency displays with multiple layouts
• Audio system visualization with album artwork and track information
• Phone and communication integration with message display
• Trip computer and real-time vehicle monitoring comprehensive data

Advanced driver assistance integration

Premium Plus and Prestige trims included sophisticated safety technologies that preview autonomous driving capabilities effectively.

Available safety system portfolio:

• Audi pre sense basic collision preparation with automatic braking
• Audi Side Assist blind spot monitoring with rear traffic alert
• Active Lane Assist with steering intervention capability
• Traffic sign recognition with speed limit display functionality
• Adaptive cruise control with stop-and-go traffic capability

Actionable takeaways:

• Standard smartphone integration eliminates aftermarket solution requirements
• Virtual Cockpit upgrade justifies Premium Plus trim consideration
• Advanced safety features may reduce insurance premium costs significantly

How reliable is the 2021 Audi A4 for long-term ownership?

The 2021 A4 received solid reliability ratings that represent continued improvement over previous Audi generations. What Car awarded an 86.6% reliability score, placing it competitively within the luxury sedan segment.

Reliability performance compared to competitors

The 86.6% What Car score places the 2021 A4 ahead of Mercedes C-Class and Alfa Romeo Giulia but behind BMW 3 Series and Volvo V60 competitors. This represents steady improvement over earlier Audi reliability concerns.

Competitive reliability ranking context:

• Above average: BMW 3 Series, Volvo V60, Genesis G70
• Good performance: 2021 Audi A4 (86.6%), Infiniti Q50, Acura TLX
• Below average: Mercedes C-Class, Alfa Romeo Giulia, Cadillac CT4

Common maintenance considerations

Most reported issues affect electrical components and infotainment systems rather than major mechanical systems. These concerns are typically covered under comprehensive warranty protection during early ownership periods.

Reported maintenance attention areas:

• Infotainment systems: Occasional software update requirements for optimal performance
• Electrical components: Rare warning light malfunctions requiring dealer attention
• DSG transmission: Major service required at 40,000 miles (expensive but essential)
• Climate control: Infrequent electronic control module calibration needs

Positive reliability factors supporting ownership:

• Engine and transmission demonstrate excellent long-term durability consistently
• Build quality remains consistently high across all production batches
• Electrical architecture shows improvement over previous generations
• Warranty coverage addresses virtually all early ownership concerns comprehensively

Actionable takeaways:

• Expect moderate maintenance costs compared to mainstream brands
• DSG service at 40k miles critical for transmission longevity
• Regular software updates prevent most electronic system issues

What are the 2021 A4's performance capabilities?

The 2021 A4 delivers engaging driving dynamics that expertly balance performance capability with luxury comfort expectations. Acceleration feels stronger than specifications suggest due to excellent torque delivery characteristics and responsive transmission programming.

Acceleration and handling performance metrics

Real-world performance consistently exceeds manufacturer claims thanks to the mild hybrid system's torque characteristics and sophisticated transmission calibration throughout the rev range.

Verified performance measurements:

• 0-60 mph (45 TFSI): 4.8 seconds with consistent repeatability
• 0-60 mph (40 TFSI): 6.3 seconds with launch control activated
• Quarter-mile: 13.5 seconds @ 102 mph
• Top speed: 130 mph electronically governed for safety
• Braking 60-0: 149 feet with premium tire compounds

Ride quality and comfort characteristics

The multi-link suspension system provides exceptional ride quality while maintaining composed handling characteristics during spirited driving. Cabin noise isolation ranks among the segment's best performers consistently.

Dynamic driving characteristics analysis:

• Composed cornering with minimal body roll through tight transitions
• Precise steering with appropriate feedback for luxury sedan expectations
• Confident braking from ventilated disc setup with excellent pedal feel
• Quiet cabin even at sustained highway cruising speeds

Suspension tuning philosophy balance:

• Comfort-oriented primary focus for daily driving scenarios
• Controlled body motions during enthusiastic driving sessions
• Effective bump absorption over deteriorated road surfaces
• Stable high-speed cruising behavior on highway stretches

Actionable takeaways:

• Performance satisfies most luxury sedan buyer expectations completely
• Ride quality excellent for daily commuting and long-distance travel
• Handling capability supports enthusiastic weekend driving adventures

How does the 2021 A4 compare against key rivals?

The 2021 A4 competed directly against established luxury sedans including BMW 3 Series, Mercedes-Benz C-Class, and emerging competitors like Genesis G70 and Infiniti Q50.

Comprehensive competitive analysis breakdown

The A4 earned recognition as a top-tier luxury sedan choice, balancing performance, efficiency, technology, and safety better than most segment competitors consistently.

A4 competitive strength analysis:

• Technology integration superior to German luxury rivals significantly
• Standard AWD while competitors charge premium for similar capability
• Fuel efficiency competitive with best-in-class performers
• Safety ratings match or exceed premium competitors

Areas where specific competitors excel:

• BMW 3 Series: Superior driving dynamics and rear-wheel drive character
• Mercedes C-Class: More luxurious interior materials and finish quality
• Genesis G70: Better warranty coverage and initial purchase value
• Infiniti Q50: Higher performance output and acceleration capability
• Lexus IS: Stronger long-term reliability reputation historically

Market positioning competitive insights:

• Best overall balance of features, performance, and efficiency
• Premium technology without overwhelming interface complexity
• Competitive pricing against established German luxury rivals
• Strong safety credentials maintain family-friendly appeal effectively

Actionable takeaways:

• A4 offers optimal overall package for most luxury sedan buyers
• Consider BMW 3 Series for maximum driving engagement priority
• Genesis G70 appeals to value-conscious luxury buyers

What fuel economy does the 2021 A4 achieve?

The 2021 A4 achieves outstanding fuel economy ratings that make it practical for daily commuting and long-distance touring despite strong performance capabilities across all driving conditions.

EPA-certified fuel economy performance:

• 45 TFSI models: 24 city / 31 highway / 27 combined mpg
• 40 TFSI models: 25 city / 34 highway / 28 combined mpg
• Real-world average: 28.7 mpg based on owner data

Real-world efficiency analysis and expectations

Actual fuel consumption typically matches EPA estimates closely based on owner reporting data. Fuelly.com data shows 28.67 mpg average across multiple vehicles and 201,402 miles of real-world driving.

Range calculation estimates:

• City range: Approximately 400 miles per tank
• Highway range: Up to 530 miles per tank
• Combined range: 450 miles typical range

Efficiency optimization factors:

• Mild hybrid system provides electric assist during acceleration phases
• Advanced turbocharger technology maintains efficiency under varying load conditions
• Direct injection optimizes combustion process for maximum fuel economy
• Aerodynamic design reduces highway drag coefficient significantly

Real-world efficiency maximization strategies:

• Eco driving mode selection maximizes fuel economy potential
• Regular maintenance schedules maintain optimal engine efficiency
• Proper tire pressure maintenance improves highway fuel economy
• Quality premium fuel ensures engine operates at peak efficiency

Annual fuel cost analysis:

• Estimated annual cost: $1,700-2,100 based on 12,000 miles annually
• Premium fuel penalty: $250-400 additional cost per year
• Efficiency advantage: Saves $300-500 versus less efficient luxury competitors

Actionable takeaways:

• 27-28 mpg combined excellent performance for luxury sedan segment
• Mild hybrid system provides measurable efficiency improvements
• Efficient highway cruising ideal for commuter-focused buyers

Frequently asked questions

Is the 2021 Audi A4 reliable for long-term ownership?

What trim level offers the best value for money?

How does the 2021 A4 compare to the BMW 3 Series?

What are the most common problems with 2021 A4?

Is premium fuel absolutely required for the 2021 A4?

How much should I expect to pay for a used 2021 A4?

Does the A4 hold its value well compared to competitors?

What's the difference between 40 TFSI and 45 TFSI models?

How expensive is maintenance compared to other luxury brands?

Should I buy a 2021 A4 in 2025?