2018 head-to-head · Midsize Car
2018 BMW 5 Series Diesel vs Cadillac CT6 Plug-in Hybrid
MPG, range and what each one really costs you to fuel, from official EPA ratings and recalculated with your own gas and electricity prices.
AWD · 3.0L 6-cyl turbo · 8-speed automatic · 30 MPG
RWD · 2.0L 4-cyl turbo · CVT · 62 MPGe + 25 MPG
On fuel costs these two are nearly tied. Driving 15,000 miles a year with $3.70/gal diesel fuel, 18¢/kWh electricity and $3.95/gal premium gas, the most efficient 2018 BMW 5 Series Diesel (30 MPG) costs about $1,850 a year to fuel and the 2018 Cadillac CT6 Plug-in Hybrid (62 MPGe + 25 MPG) about $1,830.
Your numbers
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Fuel cost over 10 years
- BMW 5 Series Diesel
- Cadillac CT6 Plug-in Hybrid
Side by side
| BMW 5 Series Diesel | Cadillac CT6 Plug-in Hybrid | |
|---|---|---|
| $1,850 | Your annual fuel cost | $1,830 |
| 30 MPG | Combined efficiency | 62 MPGe + 25 MPG |
| 26 MPG | City | 56 MPGe / 23 MPG |
| 36 MPG | Highway | 71 MPGe / 29 MPG |
| — | Electricity use (kWh/100 mi) | 54 kWh |
| — | Driving range | 430 mi |
| — | All-electric range | 31 mi |
| 99 cu ft | Passenger volume | 106 cu ft |
| 14 cu ft | Cargo volume | 10 cu ft |
| 341 g/mi | Tailpipe CO₂ (g/mi) | 144 g/mi |
| 7/10 | EPA fuel economy score | 9/10 |
| 5/10 | EPA greenhouse gas score | 10/10 |
| — | Charge time at 240V | 4.5 hrs |
| Diesel | Powertrain | Plug-in hybrid |
| Diesel | Fuel | Premium gas + electricity |
| 3.0L 6-cyl turbo | Engine / motor | 2.0L 4-cyl turbo |
| 8-speed automatic | Transmission | CVT |
| AWD | Drivetrain | RWD |
✓ marks the better value. EPA scores run 1–10 (10 is best). Volumes come from the EPA interior volume index and aren't published for every body style.
BMW 5 Series Diesel vs Cadillac CT6 Plug-in Hybrid across model years
- BMW 5 Series Diesel
- Cadillac CT6 Plug-in Hybrid
Annual fuel cost of the most efficient configuration of each model year, at your prices. Click a point to open that year.
How they differ
Per EPA interior volume figures, the Cadillac CT6 Plug-in Hybrid has more passenger space (106 vs. 99 cu ft); the BMW 5 Series Diesel has more cargo space (14 vs. 10 cu ft).
Among 74 2018 midsize cars, the BMW 5 Series Diesel ranks 36th and the Cadillac CT6 Plug-in Hybrid 35th for lowest fuel cost.
The powertrains differ: the BMW 5 Series Diesel is a diesel, while the Cadillac CT6 Plug-in Hybrid is a plug-in hybrid.
Frequently asked questions
Which is more fuel-efficient, the 2018 BMW 5 Series Diesel or the 2018 Cadillac CT6 Plug-in Hybrid?
Measured by cost to drive, the Cadillac CT6 Plug-in Hybrid. The BMW 5 Series Diesel is rated 30 MPG combined and the Cadillac CT6 Plug-in Hybrid 62 MPGe + 25 MPG (EPA, most efficient configuration of each).
How much does it cost to fuel the 2018 BMW 5 Series Diesel vs. the Cadillac CT6 Plug-in Hybrid per year?
At 15,000 miles a year with $3.70/gal diesel fuel, 18¢/kWh electricity and $3.95/gal premium gas, about $1,850 for the BMW 5 Series Diesel and $1,830 for the Cadillac CT6 Plug-in Hybrid.
Which has more cargo space?
The BMW 5 Series Diesel, with 14 cu ft of luggage volume versus 10 cu ft (EPA interior volume index).
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