BMW Z4 vs Porsche Boxster
The BMW Z4 is the more efficient of the two: it reaches 28 mpg combined versus 25 mpg for the Porsche Boxster, a 3 mpg advantage and costs about $350 less per year to fuel.
Across 5 measured categories, the BMW Z4 leads in 5. Figures are EPA test data, not manufacturer claims.
2015–2020
Porsche Boxster
Two Seaters · 35 configurations
Head-to-head specifications
| Metric | BMW Z4 | Porsche Boxster |
|---|---|---|
| Best combined MPG | 28 mpg ✓ | 25 mpg |
| Best city MPG | 25 mpg ✓ | 22 mpg |
| Best highway MPG | 33 mpg ✓ | 31 mpg |
| Lowest annual fuel costEPA estimate at 15,000 miles per year | $2,700 ✓ | $3,050 |
| Lowest CO2 output | 312 g/mi ✓ | 352 g/mi |
| Engines offered | SIDI | SIDI |
| Transmissions | Manual 6-spd, Automatic (S8), Automatic (AM-S7) | Automatic (AM-S7), Manual 6-spd |
| Drivetrains | Rear-Wheel Drive | Rear-Wheel Drive |
| Fuel types | Premium | Premium |
| EPA class | Two Seaters | Two Seaters |
| Years covered | 2015–2026 | 2015–2020 |
| Configurations on record | 25 | 35 |
Source: EPA fuel economy records via fueleconomy.gov. Best-case values across all recorded configurations for each model.
Z4 vs Boxster: common questions
Which is better on gas, the BMW Z4 or the Porsche Boxster?
The BMW Z4 is the more efficient of the two: it reaches 28 mpg combined versus 25 mpg for the Porsche Boxster, a 3 mpg advantage and costs about $350 less per year to fuel.
Which costs less to run per year?
By EPA estimates at 15,000 miles a year, the BMW Z4 runs about $2,700 a year in fuel at its most efficient configuration, versus about $3,050 for the Porsche Boxster — a difference of roughly $350 per year.
What engines do the Z4 and Boxster offer?
BMW Z4: SIDI. Porsche Boxster: SIDI.
Are they in the same vehicle class?
Yes — the EPA classifies both the BMW Z4 and the Porsche Boxster as Two Seaters, so they compete directly.
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