The Infiniti M45 does 18 mpg combined (16 city, 21.3 highway), which works out to about $2,133 a year in fuel at $3.20 a gallon and 12,000 miles. Against other V8 cars it sits above the average of 16.1 mpg.
Every Infiniti M45 engine, compared
The Infiniti M45 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.
| Engine | Combined | City / Highway | Years | Fuel per year |
|---|---|---|---|---|
| 4.5L 8-cyl | 16 / 21.3 | 2003–2010 | $2,133 |
What that actually costs
The Infiniti M45 burns a gallon every 18 miles, so 12,000 miles takes about 667 gallons a year. At $3.20 that is what the table below adds up to.
| Measure | Value |
|---|---|
| Cost per mile | $0.178 |
| Fuel per year | $2,133 |
| Fuel over five years | $10,665 |
| Against other V8 cars | −$252 a year |
| EPA's own estimate | $4,300 a year |
City or highway — who is this car for
The Infiniti M45 gives up 5.3 mpg the moment you leave the motorway — 21.3 out there against 16 in town, a 33% drop worth $597 a year. A wide gap punishes stop-and-start traffic; a narrow one means the car doesn't care where you drive it.
| Measure | Value | Reading |
|---|---|---|
| City | 16 mpg | $2,400 a year if you only drive in town |
| Highway | 21.3 mpg | $1,803 a year if you mostly commute |
| Gap | +5.3 mpg (33%) | Wide — this car dislikes traffic |
How the M45 changed over the years
Combined figure across the 7 model years the M45 was rated in, all of them at 18 mpg. Jumps usually mark a new generation or a new engine; dips often mean a heavier body or added all-wheel drive.
| Model year | Combined | City / Highway | Engines offered | Fuel per year |
|---|---|---|---|---|
| 2010 | 16 / 21 | 1 | $2,133 | |
| 2009 | 16 / 21 | 1 | $2,133 | |
| 2008 | 16 / 21 | 1 | $2,133 | |
| 2007 | 16 / 21 | 1 | $2,133 | |
| 2006 | 16 / 21 | 1 | $2,133 | |
| 2004 | 16 / 22 | 1 | $2,133 | |
| 2003 | 16 / 22 | 1 | $2,133 |
MPG is a number. Dollars per year is the answer.
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How we count
This page rests on 7 EPA ratings of the Infiniti M45 — 1 engine across 2003–2010. 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 $4,300. Full method.
Frequently asked questions
What mpg does the Infiniti M45 get?
18 mpg combined on average — 16 in the city and 21.3 on the highway, per EPA ratings across 2003–2010.
How much does a Infiniti M45 cost in fuel per year?
About $2,133 at 12,000 miles and $3.20 a gallon — roughly $10,665 over five years, or 0.178 dollars a mile.
Which M45 engine is the most economical?
The 4.5L 8-cyl at 18 mpg.
Is the M45 good on fuel compared with similar cars?
Against other V8 cars it sits above the average of 16.1 mpg, computed across 3323 ratings.
Are these real-world M45 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 M45 is $4,300 against the $2,133 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.
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