Porsche 911 Carrera 4 Cabriolet
What it costs to keep fuelled
$2,400a year, fuel only
The 2024 Porsche 911 Carrera 4 Cabriolet is EPA-rated at 20 MPG combined (18 city / 24 highway). Over 15,000 miles a year that is about 750 gallons, $2400 a year in fuel, or $0.160 per mile at $3.20/gal.
Across its full 2002–2024 run it averages 21 MPG, improving by 2.5 MPG over 16 model years.
The band is how far one gallon carries it: 20 of the 60 MPG this scale runs to. The square tick is the minicompact cars average, 22.5.
- Fuel, per year
- $2,400 at 15,000 mi
- Per mile
- $0.160
- Per kilometre
- $0.099
- Gallons burned/yr
- 750
1 mile = 1.609344 km · fuel at $3.20/gal, fixed JUL 2026
Test figure — not a road resultSOURCE·US EPA fuel-economy test data·FUEL ASSUMED AT $3.20/GAL FROM JUL 2026·REVIEWED JUL 2026
How this is worked out
- Start from the EPA combined figure for the model year — a laboratory test cycle run to a fixed procedure, not a road result. Where a year sold several engines or drivetrains, the trims are averaged and the trim count is printed beside the row so you can see how much averaging is behind it.
- Fix a pump price. This site keeps one reference price, $3.20 a US gallon, fixed JUL 2026 and printed next to every dollar figure it produces. It is an assumption with a date on it, not a quote — put your own price in.
- Fix an annual distance. Every annual figure on this site uses 15,000 miles a year, roughly the US average. A cost per year with no stated distance is not a number, it is a mood.
- Divide distance by economy for gallons, multiply by price for the year's fuel, divide price by economy for one mile. The per-kilometre line is that last figure divided by 1.609344 — the same money, in the unit most of the world drives in.
- Stop there. No depreciation, no tyres, no insurance, no servicing. This is the fuel line of the ledger and it is labelled as one; depreciation usually dwarfs everything on it.
gallons/yr = miles/yr ÷ MPG fuel $/yr = gallons/yr × $/gal cost $/mi = $/gal ÷ MPG cost $/km = cost $/mi ÷ 1.609344
The full method, the licence note, and what a test figure cannot tell you →
Re-run the ledger at another pump price
Every line above rests on one pump price. Here is the same entry re-costed at six others, because the price is the part that changes while the test sheet stays put.
| Fuel price | Per mile | 10,000 mi/yr | 15,000 mi/yr | 20,000 mi/yr |
|---|---|---|---|---|
| $2.50/gal | $0.125 | $1250 | $1875 | $2500 |
| $3.00/gal | $0.150 | $1500 | $2250 | $3000 |
| $3.20/gal | $0.160 | $1600 | $2400 | $3200 |
| $3.50/gal | $0.175 | $1750 | $2625 | $3500 |
| $4.00/gal | $0.200 | $2000 | $3000 | $4000 |
| $4.50/gal | $0.225 | $2250 | $3375 | $4500 |
| $5.00/gal | $0.250 | $2500 | $3750 | $5000 |
SOURCE·US EPA fuel-economy test data·FUEL ASSUMED AT $3.20/GAL FROM JUL 2026·REVIEWED JUL 2026
The whole service history, sheet by sheet
16 model years on file. Read down the combined column: a nameplate that got heavier shows it here long before any brochure admits it.
| Year | Combined | City | Highway | EPA fuel cost/yr | CO₂ g/mi | Trims |
|---|---|---|---|---|---|---|
| 2024 | 20 MPG | 18 | 24 | $3850 | 443 | 1 |
| 2023 | 20 MPG | 18 | 24 | $3850 | 443 | 1 |
| 2022 | 20 MPG | 18 | 24 | $3850 | 443 | 1 |
| 2021 | 20 MPG | 18 | 24 | $3850 | 443 | 1 |
| 2020 | 20 MPG | 18 | 24 | $3850 | 443 | 1 |
| 2019 | 23 MPG | 20 | 28 | $3350 | 383 | 2 |
| 2018 | 23 MPG | 20 | 28 | $3350 | 383 | 2 |
| 2017 | 23 MPG | 20 | 28 | $3350 | 383 | 2 |
| 2016 | 21.5 MPG | 19.5 | 26.5 | $3575 | 406 | 2 |
| 2015 | 21.5 MPG | 19.5 | 26.5 | $3575 | 406 | 2 |
| 2014 | 21.5 MPG | 19.5 | 26.5 | $3575 | 408 | 2 |
| 2013 | 21.5 MPG | 19.5 | 26.5 | $3575 | 408 | 2 |
| 2012 | 21 MPG | 18 | 25.5 | $3650 | 423 | 2 |
| 2011 | 21 MPG | 18 | 25.5 | $3650 | 423 | 2 |
| 2010 | 21 MPG | 18 | 25.5 | $3650 | 423 | 2 |
| 2002 | 17.5 MPG | 15 | 21.5 | $4425 | 508 | 2 |
Where a model year offered several engines or drivetrains, the figure is the average across all EPA-tested trims that year — the trim count is shown so you can see how much averaging is involved.
SOURCE·US EPA fuel-economy test data·FUEL ASSUMED AT $3.20/GAL FROM JUL 2026·REVIEWED JUL 2026
Marked against the rest of the minicompact cars bay
Among the 68 minicompact cars models tracked here, the Porsche 911 Carrera 4 Cabriolet ranks 30 on current figures, against a class average of 22.5 MPG — the square tick on the gauge above.
Closest more-efficient alternatives in the same class: Porsche Carrera 4 S Cabriolet (20.5), Porsche Carrera 4 S Coupe (20.5), Mitsubishi Eclipse Spyder (21), Porsche 911 Carrera (21), Porsche 911 Carrera Cabriolet (21).
Tailpipe CO₂ is rated at 443 grams per mile, which works out to roughly 6.6 tonnes a year at 15,000 miles.
Questions asked across the counter
What MPG does the Porsche 911 Carrera 4 Cabriolet get?
The 2024 Porsche 911 Carrera 4 Cabriolet is rated at 20 MPG combined by the EPA — 18 city and 24 highway. Across all 16 model years in the database it averages 21 MPG, ranging from 17 to 24 depending on year and trim.
How much does a Porsche 911 Carrera 4 Cabriolet cost in fuel per year?
At 20 MPG and 15,000 miles a year, it burns about 750 gallons — roughly $2400 a year with fuel at $3.20 a gallon, or $0.160 per mile. The EPA's own published annual figure for the 2024 model is $3850.
Has the Porsche 911 Carrera 4 Cabriolet become more efficient over time?
Yes. It has gone from 17.5 MPG in 2002 to 20 in 2024 — an improvement of 2.5 MPG, or 14% across 16 model years.
Is the Porsche 911 Carrera 4 Cabriolet efficient for its class?
It ranks 30 of 68 in the Minicompact Cars class on current figures, against a class average of 22.5 MPG. That is 2.5 worse than typical for the class.
Pull another logbook off the same shelf
Same class, nearest economy first — the ones a buyer is genuinely choosing between.
SOURCE·US EPA fuel-economy test data·FUEL ASSUMED AT $3.20/GAL FROM JUL 2026·REVIEWED JUL 2026
Cost per mile, per kilometre and per year are computed at a reference price of $3.20 a gallon over 15,000 miles, fixed JUL 2026 — set your own pump price. Estimates based on official test figures and average fuel prices. Real-world consumption varies with driving style, load, terrain and maintenance.
