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911Petrolvs420dDiesel
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  • Specs911 · 420d

Porsche 911 Carrera Cabriolet 991.2 vs BMW 420d Convertible G22: which one uses less fuel?

Same car, two powertrains. The simulator below calculates the gap based on your mileage and charging type.

sports car · 2017 vs 2021 · 15,000 km/an · Mixed · Petrol 95 2.03 €/L · Diesel 2.25 €/L · Methodology

Result · yearly energy cost

APorsche 911 Carrera Cabriolet 991.2

3,129 €per year

10,3 L/100 km weighted · 20.86 € per 100 km · 1 539 L per year

Gap1,576 €per year in favour of the 420d Convertible (−50 %)≈ 775 L petrol 95
BBMW 420d Convertible G22

1,553 €per year

4,6 L/100 km weighted · 10.35 € per 100 km · 692 L per year

Annual mileage
15,000 km
5,000 km50,000 km
Driving mix
Fuel price : Petrol 95 2.03 €/L · Diesel 2.25 €/Lprix-carburants.gouv.fr — moyenne nationale du 25/08/2026 ; EDF Tarif Bleu Base au 01/08/2026 ; DC autoroute : moyenne des réseaux sans abonnement
The verdict changes with your usage
ProfileSplit911420dGap
City70 % city · 25 % road · 5 % motorway3,420 €1,631 €1,789 € · 420d
Mixed30 % city · 50 % road · 20 % motorway3,129 €1,553 €1,576 € · 420d
Long-distance10 % city · 40 % road · 50 % motorway2,839 €1,499 €1,340 € · 420d

Cumulative saving for the 420d Convertible

1 year
1,576 €
3 years
4,727 €
5 years
7,878 €
10 years
15,757 €

Energy only. Excludes purchase, insurance, servicing, depreciation.

What produces these figures

WLTP combined
10.2 L/100 km · 4.5 L/100 km
Powertrain
Combustion · Combustion
Power
375 ch · 190 ch
Kerb weight
1,500 kg · 1,775 kg

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Frequently asked questions

On a 100 km mixed trip, the BMW 420d Convertible is about 50% cheaper than the Porsche 911 Carrera Cabriolet with default parameters. This ratio shifts with your actual energy prices - simulate for your profile.

The BMW 420d Convertible is cheaper across all distances with default rates. If your energy prices differ significantly, simulate to see the real impact on your budget.