41/100
2018Subcompact CarsPremium

2018 BMW 640i Convertible

EPA ID: 38606
20
City MPG
23
Combined MPG
23MPG· Average
29
Highway MPG

Fuel Economy Overview

The 2018 BMW 640i Convertible achieves an EPA-estimated 23 MPG in combined city and highway driving, with 20 MPG in the city and 29 MPG on the highway. Powered by a 3L 6-cylinder turbocharged engine paired with a automatic (s8), this subcompact cars features Rear-Wheel Drive drive.

In terms of environmental impact, the 2018 640i Convertible produces approximately 378 grams of CO2 per mile. This figure is measured under standardized EPA test conditions and represents tailpipe emissions only. For context, the average new vehicle sold in the United States produces approximately 400 grams of CO2 per mile, meaning this 640i Convertible performs better than the national average in this regard.

The estimated annual fuel cost for this vehicle is $3,000, based on 15,000 miles of driving per year and current national average fuel prices. Compared to the average new vehicle, you would save $4,250 over a 5-year period. This calculation accounts for differences in fuel consumption efficiency and provides a practical measure of long-term ownership costs attributable to fuel economy.

Energy DNA

Vehicle ClassSubcompact Cars
Fuel TypePremium
Engine3L 6-cyl
AspirationTurbocharged
TransmissionAutomatic (S8)
Drive TypeRear-Wheel Drive

Green Scorecard

CO2 Emissions378 g/mi
Start-Stop SystemEquipped
GHG Score5/10
Smog RatingN/A
Est. Annual Cost$3,000
5-Year Cost DeltaSave $4,250

Personalized Commute CalculatorEPA defaults to 55% City / 45% Hwy

55% City45% Highway

Adjust the slider to match your daily driving habits. City driving involves stop-and-go traffic under 45mph, while highway driving represents sustained speeds over 55mph.

Your Real MPG
23.2
Impact vs EPA
$-24
/ year
💨

Aerodynamic Speed Penalty

EPA highway tests average roughly 48 mph. Driving at 75 mph increases aerodynamic drag exponentially. Expect your real-world highway fuel economy to drop by roughly 15-20% at interstate speeds.

5-Year Total Cost of Ownership

Estimated Monthly Cost
$641/mo
Includes estimated depreciation, fuel, insurance, and state fees over 5 years. Does not include loan interest.
15,000 mi
Value Depreciation
Est. value lost over 60 months
$17,500
45.5%
Fuel & Electricity
Based on National Average rates ($3.50/gal)
$11,413
29.7%
Estimated Insurance
Based on vehicle class risk profile
$9,125
23.7%
State Registration Fees
Based on National Average DMV base rates
$400
1.0%
Total 5-Year Cost$38,438

Recall Intelligence

Campaign #19V684000·2019-11-08
critical
Component: BACK OVER PREVENTION: SENSING SYSTEM: CAMERA

BMW of North America, LLC (BMW) is recalling certain 2018 540d, 2018-2020 530i, 530i xDrive, 540i, 540i xDrive, M550i xDrive, M5, 530e, 530e xDrive, X3 sDrive, X3 xDrive, X3 M40i, X3 M, and 2019-2020 X4 xDrive, X4 M40i, X4 M, X7 xDrive, X7 M50i, 740Li, 740Li xDrive, 750Li, 750Li xDrive, 8 Series Convertible and Coupe 840i, 840i xDrive, M850i xDrive, X5 sDrive, X5 xDrive, X5 M50i, X6 xDrive, X6 M50i, 330i, 330i xDrive, M340i, M340i xDrive, Z4 sDrive, Z4 M40i, 740Le xDrive and 745Le xDrive, 2018-2019 640i xDrive Gran Turismo and Rolls-Royce Phantom, 2019 M850i xDrive Gran Coupe and Rolls-Royce Cullinan and 2020 Toyota Supra vehicles. The back-up camera and display settings can be adjusted such that the rear view image is no longer visible and the system will retain that setting the next time the vehicle is placed in reverse. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 111, "Rearview Mirrors."

Consequence & Remedy

Consequence: The lack of an image in the back-up camera display increases the risk of a crash.

Remedy: BMW will notify owners, and dealers will update the back-up camera software, free of charge. The recall began November 8, 2019. Owners may contact BMW customer service at 1-800-525-7417 or Rolls-Royce at 1-877-877-3735. Toyota owners may contact Toyota customer service at 1-888-270-9371.

Campaign #18V465000·2018-09-06
critical
Component: ENGINE AND ENGINE COOLING:ENGINE

BMW of North America, LLC (BMW) is recalling certain 2018 BMW 540d xDrive vehicles. The crankshaft sensor may be equipped with incorrect firmware, preventing the sensor from properly processing input from the crankshaft reluctor ring, possibly resulting in a vehicle stall. On September 12, 2018, BMW expanded the recall to a total of 5,309 vehicles including certain 2018-2019 BMW 540d xDrive, 230i M240i, M240i xDrive, X2 sDrive28i, X2 xDrive28i, X1 sDrive28i, X1 xDrive28i, 330i, 330i xDrive, 340i, 340i xDrive, 330i xDrive Gran Turismo, 530i, 530i xDrive, 540i, 540i xDrive, 530e, 530e xDrive, 640i xDrive Gran Turismo, 330e, 2019 430i Gran Coupe, 430i xDrive Gran Coupe, 440i Gran Coupe, 440i xDrive Gran Coupe, 430i, 430i xDrive, 440i, 440i xDrive, 740i, 740i xDrive, MINI Cooper, Cooper S, JCW, MINI Countryman (Cooper, Cooper All4, Cooper S, Cooper S All4, JCW All4), and MINI Clubman (Cooper, Cooper S, Cooper All4, Cooper S All4, JCW All4) vehicles.

Consequence & Remedy

Consequence: A vehicle stall can increase the risk of a crash.

Remedy: BMW will notify owners, and dealers will replace the crankshaft sensor, free of charge. The recall began September 6, 2018. Owners may contact BMW customer service at 1-800-525-7417.

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Looking for comprehensive historical data?

NHTSA FARS (Fatal Crash History) and broader generational safety trends are aggregated at the model level rather than by specific engine configurations. View the complete historical data profile for all BMW 640i Convertible configurations.

View Model History

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Fuel Cost Analysis

Annual Fuel Cost$3,000
vs. Avg Vehicle (5 yrs)Save $4,250

Based on 15,000 miles/year and current fuel prices.

Efficiency Breakdown

City20 MPG
Highway29 MPG
Combined23 MPG

Estimated Lifetime Carbon Footprint

(Based on 200,000 miles driven)

75.6 metric tons CO₂
Equivalent To:
🌳 94 tree seedlings grown for 10 yrs
✈️ 6.3 cross-country flights/yr

Data Provenance

Data directly from the EPA National Vehicle and Fuel Emissions Laboratory. The combined rating is a weighted average (55% city, 45% highway). For official figures, visit fueleconomy.gov.