Cadillac CT5 vs Mercedes-Benz S-Class: Specs Compared
Also searched as Mercedes-Benz S-Class vs Cadillac CT5 specs — both orientations show this same side-by-side comparison.
The Cadillac CT5 is the more efficient of the two: it reaches 27 mpg combined versus 26 mpg for the Mercedes-Benz S-Class, a 1 mpg advantage and costs about $100 less per year to fuel.
Across 5 measured categories, the Cadillac CT5 leads in 3. Figures are EPA test data, not manufacturer claims.
2015–2027
Mercedes-Benz S-Class
Large Cars · 106 configurations
Head-to-head specifications
| Metric | Cadillac CT5 | Mercedes-Benz S-Class |
|---|---|---|
| Best combined MPG | 27 mpg ✓ | 26 mpg |
| Best city MPG | 23 mpg | 24 mpg ✓ |
| Best highway MPG | 33 mpg ✓ | 31 mpg |
| Lowest annual fuel costEPA estimate at 15,000 miles per year | $2,800 ✓ | $2,900 |
| Lowest CO2 output | 333 g/mi | 106 g/mi ✓ |
| Engines offered | SIDI | SIDI; Mild Hybrid, 6.0, SIDI; PHEV, SIDI |
| Transmissions | Automatic (S10), Manual 6-spd | Automatic 9-spd, Automatic 7-spd |
| Drivetrains | All-Wheel Drive, Rear-Wheel Drive | All-Wheel Drive, 4-Wheel Drive, Rear-Wheel Drive |
| Fuel types | Premium | Premium, Premium and Electricity |
| EPA class | Midsize Cars | Large Cars |
| Years covered | 2020–2026 | 2015–2027 |
| Configurations on record | 52 | 106 |
Source: EPA fuel economy records via fueleconomy.gov. Best-case values across all recorded configurations for each model.
Cadillac CT5 vs Mercedes-Benz S-Class dimensions and size
The Mercedes-Benz S-Class is 14.6 inches longer than the Cadillac CT5 on a wheelbase 10.2 inches longer, and 941.4 lbs heavier. At over 200 inches, the larger of the two is past the comfortable limit of a standard 192-inch single garage bay once you allow walking room.
| Dimension | Cadillac CT5 (2026) | Mercedes-Benz S-Class (2026) | Difference |
|---|---|---|---|
| Length | 193.7 in | 208.3 in | 14.6 in |
| Width (excl. mirrors) | 74 in | 76.8 in | 2.8 in |
| Height | 57.1 in | 59.1 in | 2 in |
| Wheelbase | 116.1 in | 126.4 in | 10.2 in |
| Curb weight | 3,799 lbs | 4,740 lbs | 941 lbs |
Width excludes mirrors; add 8–12 inches for mirrors out. Figures are for the newest model year on record for each vehicle. See both drawn to scale.
Cadillac CT5 vs Mercedes-Benz S-Class: what the numbers mean
Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Cadillac CT5 burns about $2,800 of fuel annually against $2,900 for the Mercedes-Benz S-Class. That $100 yearly gap compounds to roughly $500 over five years and $800 over eight — often more than the price difference between two trims of the same vehicle, and the single largest running-cost line item separating these two.
City versus highway split: the Mercedes-Benz S-Class is the stronger commuter at 24 mpg city, while the Cadillac CT5 pulls ahead on the interstate at 33 mpg highway. If most of your driving is stop-and-go traffic the city figure is the one to weigh; for long-distance highway mileage the reverse is true, and the two vehicles effectively swap places depending on how you drive.
Powertrain choice: the Cadillac CT5 is recorded with 1 distinct engine configuration (SIDI), the Mercedes-Benz S-Class with 4 (SIDI; Mild Hybrid, 6.0, SIDI; PHEV). Across 52 recorded Cadillac CT5 configurations and 106 for the Mercedes-Benz S-Class, the wider the engine spread the more the real-world fuel efficiency depends on which version you actually buy, so check the specific model year and drivetrain rather than the headline number.
Drivetrain and class: the Cadillac CT5 is offered with All-Wheel Drive, Rear-Wheel Drive, the Mercedes-Benz S-Class with All-Wheel Drive, 4-Wheel Drive, Rear-Wheel Drive. All-wheel drive typically costs one to two mpg combined against the same vehicle in front- or rear-wheel drive, which is worth remembering when the gap between these two is small. The EPA classes them as Midsize Cars and Large Cars respectively — the class drives the interior volume, cargo space and passenger space each one is measured against.
Tailpipe emissions: at their cleanest configurations the Mercedes-Benz S-Class emits 106 g/mile of CO2 versus 333 g/mile for the Cadillac CT5. Emissions track fuel consumption almost exactly, so the cleaner vehicle here is also the cheaper one to fuel.
CT5 vs S-Class: common questions
Which is better on gas, the Cadillac CT5 or the Mercedes-Benz S-Class?
The Cadillac CT5 is the more efficient of the two: it reaches 27 mpg combined versus 26 mpg for the Mercedes-Benz S-Class, a 1 mpg advantage and costs about $100 less per year to fuel.
Which costs less to run per year?
By EPA estimates at 15,000 miles a year, the Cadillac CT5 runs about $2,800 a year in fuel at its most efficient configuration, versus about $2,900 for the Mercedes-Benz S-Class — a difference of roughly $100 per year.
What engines do the CT5 and S-Class offer?
Cadillac CT5: SIDI. Mercedes-Benz S-Class: SIDI; Mild Hybrid, 6.0, SIDI; PHEV, SIDI.
Are they in the same vehicle class?
The EPA classifies the Cadillac CT5 as Midsize Cars and the Mercedes-Benz S-Class as Large Cars, so they aren't a like-for-like match on size.
More CT5 comparisons
More S-Class comparisons
Comparison id: cadillac-ct5-vs-mercedes-benz-s-class