The BMW 645Ci does 19 mpg combined (16 city, 24 highway), which works out to about $2,021 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 BMW 645Ci engine, compared
The BMW 645Ci 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 |
|---|---|---|---|---|
| 4.4L 8-cyl | 16 / 24 | 2004–2005 | $2,021 |
What that actually costs
The BMW 645Ci burns a gallon every 19 miles, so 12,000 miles takes about 632 gallons a year. At $3.20 that is what the table below adds up to.
| Measure | Value |
|---|---|
| Cost per mile | $0.168 |
| Fuel per year | $2,021 |
| Fuel over five years | $10,105 |
| Against other V8 cars | −$364 a year |
| EPA's own estimate | $4,050 a year |
City or highway — who is this car for
The BMW 645Ci gives up 8 mpg the moment you leave the motorway — 24 out there against 16 in town, a 50% drop worth $800 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 | 24 mpg | $1,600 a year if you mostly commute |
| Gap | +8 mpg (50%) | Wide — this car dislikes traffic |
How the 645Ci changed over the years
Combined figure across the 2 model years the 645Ci was rated in, all of them at 19 mpg.
| Model year | Combined | City / Highway | Engines offered | Fuel per year |
|---|---|---|---|---|
| 2005 | 16 / 24 | 1 | $2,021 | |
| 2004 | 16 / 24 | 1 | $2,021 |
MPG is a number. Dollars per year is the answer.
- Fuel profile built from your actual mileage and local prices
- Fuel tracker: what you really spend, month by month
- Insurance and fuel folded into 5-year cost to own
- Compare any two cars on total cost, not sticker price
- No ads, no tracking — and much more
How we count
This page rests on 2 EPA ratings of the BMW 645Ci — 1 engine across 2004–2005. 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 $4,050. Full method.
Frequently asked questions
What mpg does the BMW 645Ci get?
19 mpg combined on average — 16 in the city and 24 on the highway, per EPA ratings across 2004–2005.
How much does a BMW 645Ci cost in fuel per year?
About $2,021 at 12,000 miles and $3.20 a gallon — roughly $10,105 over five years, or 0.168 dollars a mile.
Which 645Ci engine is the most economical?
The 4.4L 8-cyl at 19 mpg.
Is the 645Ci 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 645Ci figures?
No — they are EPA laboratory ratings, the same ones printed on the window sticker, and EPA's own annual fuel estimate for the BMW 645Ci is $4,050 against the $2,021 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.
Mark ForCar as a preferred source and our data shows up first in your Google results. One click, no account.