The Cadillac CT6 does 22.5 mpg combined (19.5 city, 28.1 highway), which works out to about $1,707 a year in fuel at $3.20 a gallon and 12,000 miles. Engine choice matters more than you'd think: 2L 4-cyl does 25.8 mpg while 4.2L 8-cyl does 17 — a difference of $771 a year. Against other V6 cars it sits above the average of 19.9 mpg.
Every Cadillac CT6 engine, compared
Gas mileage on the Cadillac CT6 ranges from 25.8 down to 17 depending on which engine sits under the bonnet — a spread of $771 a year across 5 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 |
|---|---|---|---|---|
| 2L 4-cyl | 22.5 / 31 | 2016–2019 | $1,488 | |
| 2L 4-cyl Hybrid | 23 / 29 | 2017–2018 | $1,506 | |
| 3L 6-cyl | 18 / 26 | 2016–2018 | $1,829 | |
| 3.6L 6-cyl | 18 / 27 | 2017–2020 | $1,829 | |
| 4.2L 8-cyl | 14 / 25 | 2019–2020 | $2,259 |
What that actually costs
The Cadillac CT6 burns a gallon every 22.5 miles, so 12,000 miles takes about 533 gallons a year. At $3.20 that is what the table below adds up to.
| Measure | Value |
|---|---|
| Cost per mile | $0.142 |
| Fuel per year | $1,707 |
| Fuel over five years | $8,535 |
| Against other V6 cars | −$223 a year |
| EPA's own estimate | $3,288 a year |
City or highway — who is this car for
The Cadillac CT6 gives up 8.6 mpg the moment you leave the motorway — 28.1 out there against 19.5 in town, a 44% drop worth $602 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 | 19.5 mpg | $1,969 a year if you only drive in town |
| Highway | 28.1 mpg | $1,367 a year if you mostly commute |
| Gap | +8.6 mpg (44%) | Wide — this car dislikes traffic |
How the CT6 changed over the years
The CT6 peaked in 2017 at 24 mpg (21 city, 28.7 highway) and was at its thirstiest in 2020 at 19 — 5 mpg apart, or $421 a year in fuel between buying one year and the other. The 2020 car does 19. 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 |
|---|---|---|---|---|
| 2020 | 16 / 26 | 2 | $2,021 | |
| 2019 | 18.7 / 28.7 | 3 | $1,745 | |
| 2018 | 21 / 28.3 | 3 | $1,620 | |
| 2017 | 21 / 28.7 | 3 | $1,600 | |
| 2016 | 20 / 28 | 2 | $1,670 |
MPG is a number. Dollars per year is the answer.
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How we count
This page rests on 13 EPA ratings of the Cadillac CT6 — 5 engines across 2016–2020. 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 $3,288. Full method.
Frequently asked questions
What mpg does the Cadillac CT6 get?
22.5 mpg combined on average — 19.5 in the city and 28.1 on the highway, per EPA ratings across 2016–2020.
How much does a Cadillac CT6 cost in fuel per year?
About $1,707 at 12,000 miles and $3.20 a gallon — roughly $8,535 over five years, or 0.142 dollars a mile.
Which CT6 engine is the most economical?
The 2L 4-cyl at 25.8 mpg, against 17 for the 4.2L 8-cyl — a difference of about $771 a year.
Is the CT6 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 CT6 figures?
No — they are EPA laboratory ratings, the same ones printed on the window sticker, and EPA's own annual fuel estimate for the Cadillac CT6 is $3,288 against the $1,707 we compute at 12,000 miles. Expect a little worse in practice: the spread between the 28 and 17 mpg versions of this car is smaller than the spread between two drivers of the same one.
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