Bmw 3 Series vs Audi A4: Compare by Reg (2026)
Side-by-side comparison of the Bmw 3 Series and Audi A4, covering MOT pass rates, running costs, common faults, and overall reliability. Based on 1,297,627 real MOT tests.
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Quick Verdict
The Bmw 3 Series edges ahead in this comparison with a 83% MOT pass rate versus 83% for the Audi A4. The difference is modest, so both are reasonable choices. The Bmw 3 Series has a slight reliability advantage, while the Audi A4 may offer other benefits depending on your priorities.
Bmw 3 Series
83%
MOT pass rate
806,092 tests
Audi A4
83%
MOT pass rate
491,535 tests
Full Comparison: Bmw 3 Series vs Audi A4
| Category | Bmw 3 Series | Audi A4 |
|---|---|---|
| MOT Pass Rate | 83% | 83% |
| MOT Fail Rate | 17% | 17% |
| vs National Avg | +1 pts | +1 pts |
| Est. Fuel Cost (8,000 mi/yr) | £1,076Winner | £1,434 |
| Insurance Group | 25-35 | 25-35 |
| Est. Depreciation/yr | £2,000-£3,500 | £2,000-£3,500 |
| Engine Size | 2.2L | 2.1L |
| Fuel Type(s) | Diesel, Petrol | Petrol, Diesel |
| Segment | Premium | Premium |
| Avg Mileage | 105,806 miWinner | 120,108 mi |
| MOT Tests Analysed | 806,092 | 491,535 |
| Model Years | 32 years | 27 years |
| Best Year | 2021 (93%) | 2021 (96%)Winner |
| Worst Year | 2000 (77%)Winner | 1995 (61%) |
| Reliability Trend | Improving | Improving |
Common Problems Comparison
Bmw 3 Series Known Issues
- •DPF and emissions issues (diesel models)
- •Higher tyre and brake wear (larger engine)
- •Suspension wear on older models
- •Lighting defects (common on all cars)
Audi A4 Known Issues
- •DPF and emissions issues (diesel models)
- •Higher tyre and brake wear (larger engine)
- •Suspension wear on older models
- •Lighting defects (common on all cars)
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Bmw 3 Series vs Audi A4 FAQ
Which is more reliable, the Bmw 3 Series or Audi A4?
Based on MOT data, the Bmw 3 Series is more reliable with a 83% pass rate, compared to 83% for the Audi A4.
Which is cheaper to run?
At 8,000 miles per year, the Bmw 3 Series costs around £1,076 in fuel, while the Audi A4 costs around £1,434. The Bmw 3 Series is cheaper on fuel. Insurance, depreciation, and repair costs also factor into total running costs.
Should I buy a Bmw 3 Series or Audi A4?
The Bmw 3 Series edges ahead in this comparison with a 83% MOT pass rate versus 83% for the Audi A4. The difference is modest, so both are reasonable choices. The Bmw 3 Series has a slight reliability advantage, while the Audi A4 may offer other benefits depending on your priorities.
Bmw 3 Series Running Costs
Full breakdown of annual costs, reliability, and MOT data
Audi A4 Running Costs
Full breakdown of annual costs, reliability, and MOT data
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