The BMW 340i does 25 mpg combined (21.7 city, 31.2 highway), which works out to about $1,536 a year in fuel at $3.20 a gallon and 12,000 miles. Engine choice matters more than you'd think: 3L 6-cyl Hybrid does 26 mpg while 3L 6-cyl does 24.5 — a difference of $90 a year. Against other V6 cars it sits above the average of 19.9 mpg.
Every BMW 340i engine, compared
Gas mileage on the BMW 340i ranges from 26 down to 24.5 depending on which engine sits under the bonnet — a spread of $90 a year across 2 versions of the same car. Picking the right one often saves more fuel than picking a different car altogether. Yearly cost assumes 12,000 miles at $3.20 a gallon.
| Engine | Combined | City / Highway | Years | Fuel per year |
|---|---|---|---|---|
| 3L 6-cyl Hybrid | 23 / 31 | 2023–2024 | $1,477 | |
| 3L 6-cyl | 21 / 31.3 | 2016–2019 | $1,567 |
What that actually costs
The BMW 340i burns a gallon every 25 miles, so 12,000 miles takes about 480 gallons a year. At $3.20 that is what the table below adds up to.
| Measure | Value |
|---|---|
| Cost per mile | $0.128 |
| Fuel per year | $1,536 |
| Fuel over five years | $7,680 |
| Against other V6 cars | −$394 a year |
| EPA's own estimate | $3,075 a year |
City or highway — who is this car for
The BMW 340i gives up 9.5 mpg the moment you leave the motorway — 31.2 out there against 21.7 in town, a 44% drop worth $539 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 | 21.7 mpg | $1,770 a year if you only drive in town |
| Highway | 31.2 mpg | $1,231 a year if you mostly commute |
| Gap | +9.5 mpg (44%) | Wide — this car dislikes traffic |
How the 340i changed over the years
The 340i peaked in 2024 at 26 mpg (23 city, 31 highway) and was at its thirstiest in 2019 at 23 — 3 mpg apart, or $193 a year in fuel between buying one year and the other. The 2024 car does 26. 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 |
|---|---|---|---|---|
| 2024 | 23 / 31 | 1 | $1,477 | |
| 2023 | 23 / 31 | 1 | $1,477 | |
| 2019 | 20 / 29 | 1 | $1,670 | |
| 2018 | 21 / 32 | 1 | $1,536 | |
| 2017 | 21 / 32 | 1 | $1,536 | |
| 2016 | 22 / 32 | 1 | $1,536 |
MPG is a number. Dollars per year is the answer.
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How we count
This page rests on 6 EPA ratings of the BMW 340i — 2 engines across 2016–2024. 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 $3,075. Full method.
Frequently asked questions
What mpg does the BMW 340i get?
25 mpg combined on average — 21.7 in the city and 31.2 on the highway, per EPA ratings across 2016–2024.
How much does a BMW 340i cost in fuel per year?
About $1,536 at 12,000 miles and $3.20 a gallon — roughly $7,680 over five years, or 0.128 dollars a mile.
Which 340i engine is the most economical?
The 3L 6-cyl Hybrid at 26 mpg, against 24.5 for the 3L 6-cyl — a difference of about $90 a year.
Is the 340i good on fuel compared with similar cars?
Against other V6 cars it sits above the average of 19.9 mpg, computed across 4940 ratings.
Are these real-world 340i 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 340i is $3,075 against the $1,536 we compute at 12,000 miles. Expect a little worse in practice: the spread between the 26 and 23 mpg versions of this car is smaller than the spread between two drivers of the same one.
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