The 2018 Cadillac CT6 Plug-In, with its 25 MPG combined rating, occupies an interesting niche. It’s not aimed at the hyper-efficiency crowd, nor is it a full-bore performance sedan. Instead, it targets buyers who want a taste of electric driving with a luxury experience, and who are willing to accept middling gas mileage when the battery is depleted. This is a sedan, and its owners likely prioritize a smooth ride, quiet cabin, and advanced technology over fuel savings.

City and highway performance

The EPA estimates the CT6 Plug-In at 23 MPG in the city and 29 MPG on the highway. The city figure reflects the stop-and-go nature of urban driving, which tends to favor electric vehicles. When the battery is charged, much of your city driving can be done on electric power alone, improving efficiency. The 29 MPG highway rating is more representative of what you’ll see on longer road trips, where the gasoline engine plays a greater role. While 29 MPG isn’t terrible for a large sedan, it’s not exactly earth-shattering either. The CT6 Plug-In’s transmission, described as “automatic (variable gear ratios)” also plays a role. This eCVT is designed for smoothness and efficiency, optimizing the blend of electric and gasoline power depending on driving conditions.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Cadillac CT6 Plug-In at $2,300. This figure is based on driving 15,000 miles per year and using national average fuel prices. Keep in mind that your actual fuel costs will depend on your driving habits, the type of fuel you use, and local fuel prices. If you frequently charge the battery and drive primarily on electric power, your annual fuel costs will be significantly lower. Conversely, if you rarely plug in the car and drive mostly on the gasoline engine, you’ll likely exceed the $2,300 estimate. You can check CT6 MPG across all years to view the fuel economy of other cars in the CT6 family.

Real-world expectations

The CT6 Plug-In’s real-world fuel economy can vary significantly depending on several factors. The most important is how frequently you charge the battery. If you can consistently plug in the vehicle and use the available electric range (around 30 miles), you’ll see a dramatic improvement in overall fuel economy. However, once the battery is depleted, the CT6 Plug-In operates solely on its 2.0L turbocharged four-cylinder engine, and its MPG will drop closer to the EPA’s highway rating. Driving style also plays a role. Aggressive acceleration and high speeds will reduce fuel economy whether you’re running on electric or gasoline power.

How it compares

Compared to other plug-in hybrid luxury sedans of its era, the 2018 CT6 Plug-In’s fuel economy falls somewhere in the middle. For example, the BMW 530e achieved a combined rating of 27 MPG, offering slightly better efficiency. Conversely, the Mercedes-Benz C350e only managed 25 MPG combined, similar to the CT6 Plug-In. These differences matter to the buyer cross-shopping these models who understands the nuances of how each manufacturer approaches fuel efficiency. Even when you compare to all Cadillac fuel economy data, you can see how Cadillac is working to make its cars have better range.

Tips to maximize efficiency

Consistent charging is the key to maximizing the CT6 Plug-In’s efficiency. Make it a habit to plug in the vehicle whenever it’s parked at home or at work. This will ensure that you have a full battery available for your daily commutes and errands, allowing you to drive primarily on electric power and reduce your gasoline consumption.

Use the CT6 Plug-In’s driving modes strategically. The “Tour” mode is designed for comfortable and efficient cruising. The “Sport” mode prioritizes performance and will reduce fuel economy. The “Hold” mode can be used to preserve the battery’s charge for later use, such as when you anticipate driving in stop-and-go traffic.

Practice smooth and gradual acceleration. Avoid hard acceleration and braking, as these driving habits consume more energy, whether you’re running on electric power or gasoline. Maintaining a steady speed and anticipating traffic flow can significantly improve your fuel economy.

Pay attention to tire pressure. Properly inflated tires reduce rolling resistance, which improves fuel efficiency. Check your tire pressure regularly and inflate them to the recommended levels specified in the vehicle’s owner’s manual.

Minimize unnecessary weight. Carrying excessive cargo in your vehicle can reduce fuel economy. Remove any unnecessary items from the trunk and passenger area to reduce the vehicle’s overall weight.