FX45

Infiniti FX45 MPG

Infiniti FX45 gas mileage averages 14.8 mpg combined — about $2,595 a year in fuel at today's prices, or $12,975 over five years. Below: every engine compared, because the gap between versions is usually wider than the gap between models.

EPA fueleconomy.gov · 1 engines · 2003–2008 · Updated Sep 19, 2026
Quick answer

The Infiniti FX45 does 14.8 mpg combined (13.2 city, 17.5 highway), which works out to about $2,595 a year in fuel at $3.20 a gallon and 12,000 miles. Against other V8 cars it sits below the average of 16.1 mpg.

Every Infiniti FX45 engine, compared

The Infiniti FX45 was rated in a single specification, so its gas mileage does not vary by version — only by model year. Yearly cost assumes 12,000 miles at $3.20 a gallon.

FIG.01·Infiniti FX45 gas mileage by engine
EngineCombinedCity / HighwayYearsFuel per year
4.5L 8-cyl14.813.2 / 17.52003–2008$2,595
ROWS 1·SOURCE EPA fueleconomy.gov + ForCar

What that actually costs

The Infiniti FX45 burns a gallon every 14.8 miles, so 12,000 miles takes about 811 gallons a year. At $3.20 that is what the table below adds up to.

FIG.02·Infiniti FX45 fuel cost
MeasureValue
Cost per mile$0.216
Fuel per year$2,595
Fuel over five years$12,975
Against other V8 cars+$210 a year
EPA's own estimate$5,208 a year
ROWS 5·SOURCE ForCar, computed from EPA ratings

City or highway — who is this car for

The Infiniti FX45 gives up 4.3 mpg the moment you leave the motorway — 17.5 out there against 13.2 in town, a 33% drop worth $715 a year. A wide gap punishes stop-and-start traffic; a narrow one means the car doesn't care where you drive it.

FIG.03·Infiniti FX45 city versus highway
MeasureValueReading
City13.2 mpg$2,909 a year if you only drive in town
Highway17.5 mpg$2,194 a year if you mostly commute
Gap+4.3 mpg (33%)Wide — this car dislikes traffic
ROWS 3·SOURCE EPA fueleconomy.gov + ForCar

How the FX45 changed over the years

The FX45 peaked in 2007 at 15 mpg (13 city, 17 highway) and was at its thirstiest in 2008 at 14 — 1 mpg apart, or $183 a year in fuel between buying one year and the other. The 2008 car does 14. Jumps usually mark a new generation or a new engine; dips often mean a heavier body or added all-wheel drive.

FIG.04·Infiniti FX45 gas mileage by model year
Model yearCombinedCity / HighwayEngines offeredFuel per year
20081413 / 171$2,743
20071513 / 171$2,560
20061513 / 171$2,560
20051514 / 181$2,560
20041513 / 181$2,560
20031513 / 181$2,560
ROWS 6·SOURCE EPA fueleconomy.gov + ForCar
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How we count

This page rests on 6 EPA ratings of the Infiniti FX45 — 1 engine across 2003–2008. The mileage is EPA's laboratory figure, unchanged; the yearly bill is ours, at 12,000 miles and $3.20 a gallon, against EPA's own estimate of $5,208. Full method.

Frequently asked questions

What mpg does the Infiniti FX45 get?

14.8 mpg combined on average — 13.2 in the city and 17.5 on the highway, per EPA ratings across 2003–2008.

How much does a Infiniti FX45 cost in fuel per year?

About $2,595 at 12,000 miles and $3.20 a gallon — roughly $12,975 over five years, or 0.216 dollars a mile.

Which FX45 engine is the most economical?

The 4.5L 8-cyl at 14.8 mpg.

Is the FX45 good on fuel compared with similar cars?

Against other V8 cars it sits below the average of 16.1 mpg, computed across 3323 ratings.

Are these real-world FX45 figures?

No — they are EPA laboratory ratings, the same ones printed on the window sticker, and EPA's own annual fuel estimate for the Infiniti FX45 is $5,208 against the $2,595 we compute at 12,000 miles. Expect a little worse in practice: the spread between the city and highway figures is smaller than the spread between two drivers of the same one.

Gas mileage ratings from EPA fueleconomy.gov, unadjusted. Running cost computed by ForCar at 12,000 miles a year and $3.20 a gallon. Last updated Sep 2026. — ForCar Reviewed by , founder of ForCar.
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