EPA ratings · 2018 · BMW · 6 Series
2018 BMW 6 Series Fuel Economy
EPA rates the 2018 BMW 6 Series's 10 trims from 19 to 23 MPG combined, 650i xDrive Convertible to 640i Convertible. The table below prices every trim per mile at a fuel price and mileage you can change.
EPA ratings by trim
| Trim | Engine | Transmission | Drive | City | Hwy | Combined |
|---|---|---|---|---|---|---|
| 640i Convertible · Premium | 3 L, 6 cyl | Automatic (S8) | Rear-Wheel Drive | 20 | 29 | 23 MPG |
| 640i Gran Coupe · Premium | 3 L, 6 cyl | Automatic (S8) | Rear-Wheel Drive | 20 | 29 | 23 MPG |
| 640i xDrive Convertible · Premium | 3 L, 6 cyl | Automatic (S8) | All-Wheel Drive | 19 | 28 | 22 MPG |
| 640i xDrive Gran Coupe · Premium | 3 L, 6 cyl | Automatic (S8) | All-Wheel Drive | 19 | 28 | 22 MPG |
| 640i xDrive Gran Turismo · Premium | 3 L, 6 cyl | Automatic (S8) | All-Wheel Drive | 20 | 28 | 23 MPG |
| 650i Convertible · Premium | 4.4 L, 8 cyl | Automatic (S8) | Rear-Wheel Drive | 17 | 25 | 20 MPG |
| 650i Gran Coupe · Premium | 4.4 L, 8 cyl | Automatic (S8) | Rear-Wheel Drive | 17 | 25 | 20 MPG |
| 650i xDrive Convertible · Premium | 4.4 L, 8 cyl | Automatic (S8) | All-Wheel Drive | 16 | 25 | 19 MPG |
| 650i xDrive Gran Coupe · Premium | 4.4 L, 8 cyl | Automatic (S8) | All-Wheel Drive | 16 | 25 | 19 MPG |
| Alpina B6 xDrive Gran Coupe · Premium | 4.4 L, 8 cyl | Automatic (S8) | All-Wheel Drive | 16 | 25 | 19 MPG |
City and highway are EPA's adjusted label figures; combined is the 55/45 blend printed on the window sticker. For electric and plug-in trims the MPG columns are MPGe, and the kWh per 100 miles is the figure a charging cost actually turns on; EPA measures it at the wall, so charging losses are already in it. Unrounded combined figures, where EPA publishes them: 640i Convertible 23.3335; 640i Gran Coupe 23.3335; 640i xDrive Convertible 22.4976; 640i xDrive Gran Coupe 22.4976; 640i xDrive Gran Turismo 22.8452; 650i Convertible 19.7998; 650i Gran Coupe 19.7998; 650i xDrive Convertible 19.1576; 650i xDrive Gran Coupe 19.1576; Alpina B6 xDrive Gran Coupe 19.1576.
What the rating costs per mile
The rating divided by a price, times your miles. It starts at EIA's current U.S. averages and EPA's 15,000 miles so the right-hand column is comparable; type your own pump price, home rate and mileage over them.
| Trim | Runs on | Rated | Per mile | Per year | EPA's figure |
|---|---|---|---|---|---|
| 640i Convertible | Premium Gasoline | 23 MPG | 18.6¢ | $2,794 | $3,550 |
| 640i Gran Coupe | Premium Gasoline | 23 MPG | 18.6¢ | $2,794 | $3,550 |
| 640i xDrive Convertible | Premium Gasoline | 22 MPG | 19.5¢ | $2,921 | $3,750 |
| 640i xDrive Gran Coupe | Premium Gasoline | 22 MPG | 19.5¢ | $2,921 | $3,750 |
| 640i xDrive Gran Turismo | Premium Gasoline | 23 MPG | 18.6¢ | $2,794 | $3,550 |
| 650i Convertible | Premium Gasoline | 20 MPG | 21.4¢ | $3,213 | $4,100 |
| 650i Gran Coupe | Premium Gasoline | 20 MPG | 21.4¢ | $3,213 | $4,100 |
| 650i xDrive Convertible | Premium Gasoline | 19 MPG | 22.5¢ | $3,382 | $4,350 |
| 650i xDrive Gran Coupe | Premium Gasoline | 19 MPG | 22.5¢ | $3,382 | $4,350 |
| Alpina B6 xDrive Gran Coupe | Premium Gasoline | 19 MPG | 22.5¢ | $3,382 | $4,350 |
Per mile = price ÷ rated MPG (gasoline) or price per kWh × kWh per 100 miles ÷ 100 (electricity). Per year = per mile × miles. EPA's figure is its own annual fuel cost at 15,000 miles, 55% city, and the national price in force when the file was built; it will differ from the middle columns whenever the price here differs. A plug-in hybrid is shown once on each fuel; its real cost sits between them, by how much of its driving is on the battery.
Fuel only — before depreciation, insurance, maintenance or tires, which the True Cost per Mile Calculator adds. Most drivers land below the rating; the True MPG Calculator measures your own from two fill-ups.
EPA's own figures, and why they differ
The “EPA's figure” column is EPA's annual fuel cost from the same file: 15,000 miles, 55% city, and the national fuel price fueleconomy.gov was using on the day the file was built (2026-09-29). fueleconomy.gov recomputes its page every week at the current price, so its number and the file's drift apart between file dates; the middle columns here use a price you can see and change, which is the only honest way to compare two cars. EPA also prints a five-year “you save/spend” against the average new vehicle (spends $5,750 for the 640i Convertible); it rests on the same assumptions and is not repeated here as a result.
Every figure on this page is a rating, not a measurement of any particular car. The site never calls a rating wrong; it shows what your own price and miles do to it. See the model on fueleconomy.gov.
Other model years of the BMW 6 Series: 2019, 2017, 2016, 2015, 2014, 2013, 2012, 2010, 2009, 2008, 2007, 2006, 2005, 2004, 1989, 1988, 1987, 1986, 1985, 1984.
Related tools
Price the same miles on gasoline and on electricity, using your fuel price, your utility rate, and each car's rated efficiency.
Open tool →True MPG CalculatorYour car's real fuel economy from two odometer readings and a fill-up — and how far it falls from its EPA rating.
Open tool →Commute Cost CalculatorWhat getting to work costs per day, per month, and per year — energy only, or all-in at the IRS standard mileage rate.
Open tool →Gas Prices by Region and StateThis week's average price of regular gasoline for the U.S., every state and ten cities, from EIA's weekly survey — a dated figure to start from, never one assumed for you.
Open tool →Electricity Prices by StateThe average residential price of electricity in every state, by month, from EIA's utility filings — and what each rate does to a mile in an electric car.
Open tool →Informational only — published averages for scale and comparison, not a quote for any pump, utility or vehicle. Your own price is the one that counts, and every calculator on this site takes it as an input.
Ratings: U.S. EPA and U.S. DOE, fueleconomy.gov vehicles.csv dated 2026-09-29 (EPA record ids 38606, 38624, 38607, 38625, 39435, 38608, 38626, 38609, 38627, 38628). Prices: EIA, U.S. regular gasoline week of October 19, 2026; U.S. residential electricity August 2026. Snapshots refreshed monthly.