Car comparison

BMW 6 Series (E63) 645CivsBMW 6 Series Convertible (F12) 640i

Compare specs, acceleration, fuel consumption, dimensions, practicality, and estimated running costs side by side.

New comparison

BMW 6 Series (E63)

645Ci

333 hp4398 ccGasolineRWDAutomaticNaturally aspiratedCoupe2003-2005
VS

BMW 6 Series Convertible (F12)

640i

320 hp2979 ccGasolineAWDAutomaticTurbochargedCabriolet / convertible2013-2015

Comparison overview

Use the estimates as comparison hints and verify exact figures before making decisions.

Best choices

BMW 6 Series (E63) 645Ci

  • Fastest top speed
    265 km/h
    165 mph Unrestricted
    250 km/h
    155 mph Restricted
  • Most powerful
    333 hp
    248 kW
  • Highest torque
    450 Nm
    332 lb-ft
  • Lightest
    1,695 kg
    3,737 lb
  • Best power-to-weight
    196 hp/t
    147 kW/t
    5.1 kg/hp
  • Largest trunk
    450 L
  • Best overall score
    63/100
  • Best performance score
    68/100
  • Best practicality score
    53/100

BMW 6 Series Convertible (F12) 640i

  • Quickest 0-100 km/h
    5.4 s
  • Lowest combined fuel consumption
    8.4 L/100 km
    28.0 mpg US
    33.6 mpg UK
  • Lowest city consumption
    11.4 L/100 km
    20.6 mpg US
    24.8 mpg UK
  • Lowest highway consumption
    6.6 L/100 km
    35.6 mpg US
    42.8 mpg UK
  • Lowest CO2 emissions
    195 g/km
  • Best estimated range
    833 km
    518 mi
  • Best economy score
    84/100

Specification comparison

Specification comparison
ModelBMW6 Series (E63)645CiBMW6 Series Convertible (F12)640i
Power
333hp248kW
320hp239kW
Torque
450Nm332lb-ft
450Nm332lb-ft
Curb weight
1,695kg3,737lb
1,910kg4,211lb
Gross weight
2,065kg4,553lb
2,400kg5,291lb
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Calculated
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Calculated
To 99% top speed
79.6s99% target: 262 km/h / 163 mph
Calculated
79.8s99% target: 257 km/h / 160 mph
Calculated
0-100 km/h
5.8s
5.4s
0-200 km/h
20.3s
Calculated
20.3s
Calculated
0-60 mph
5.5s
Calculated
5.1s
Calculated
Fuel consumption
10.9L/100 km21.6mpg US25.9mpg UK
8.4L/100 km28mpg US33.6mpg UK
Fuel consumption city
16.1L/100 km14.6mpg US17.5mpg UK
11.4L/100 km20.6mpg US24.8mpg UK
Fuel consumption highway
8L/100 km29.4mpg US35.3mpg UK
6.6L/100 km35.6mpg US42.8mpg UK
Quarter mile
13.9s
Calculated
13.6s
Calculated
Power-to-weight
196hp/t147kW/t89hp/1000 lb
Calculated
168hp/t125kW/t76hp/1000 lb
Calculated
Torque-to-weight
265Nm/t178lb-ft/ton
Calculated
236Nm/t158lb-ft/ton
Calculated
Estimated range
642km399mi
Calculated
833km518mi
Calculated
Displacement
4,398cc268cu in
2,979cc182cu in
Length
4,820mm190in
4,894mm193in
Width
1,855mm73in
1,894mm75in
Height
1,373mm54in
1,365mm54in
Wheelbase
2,780mm109in
2,855mm112in
Front track
1,558mm61in
1,600mm63in
Rear track
1,592mm63in
1,665mm66in
Ground clearance-
123mm5in
Trunk volume
450L
300L
Max trunk volume-
350L
Doors
2
2
Seats
4
4
Fuel tank
70L
70L
CO2 emissions
264g/km
195g/km

Performance charts

Use the estimates as comparison hints and verify exact figures before making decisions.

Dyno simulation

Estimated stock-style power and torque curves by engine speed.

BMW 6 Series (E63) 645CiBMW 6 Series Convertible (F12) 640iPowerTorque
  • BMW 6 Series (E63) 645Ci: Power / Torque
  • BMW 6 Series Convertible (F12) 640i: Power / Torque
Dyno simulation data table
VehiclePeak power RPMPeak torque RPMMax engine speed
BMW6 Series (E63)645Ci6,100 rpm3,600 rpm6,350 rpm
BMW6 Series Convertible (F12)640i5,800-6,000 rpm1,300-4,500 rpm6,250 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricBMW6 Series (E63)645CiBMW6 Series Convertible (F12)640i
Acceleration checkpoints
0-60 mph
0-97 km/h
5.5 s
5.1 s
0-100 km/h
0-62 mph
5.8 s
5.4 s
0-200 km/h
0-124 mph
20.3 s
20.3 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Likely limited
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Likely limited
Drag race simulation
60 ft
18 m
2.3 s
2.2 s
330 ft
101 m
6.1 s
5.9 s
1/8 mile
201 m
9.1 s
8.8 s
1000 ft
305 m
11.7 s
11.4 s
1/4 mile
402 m
13.9 s
13.6 s
Trap speed
1/4 mile
402 m
169 km/h
105 mph
169 km/h
105 mph

Power comparison

Bar comparison chart for Power. Higher is better · hp / kW

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
333 hp
248 kW
BMW6 Series Convertible (F12)640i
320 hp
239 kW

BMW 6 Series (E63) 645Ci has 13 hp more than BMW 6 Series Convertible (F12) 640i.

The biggest power difference is between BMW 6 Series Convertible (F12) 640i and BMW 6 Series (E63) 645Ci: 13 hp (10 kW).

Torque comparison

Bar comparison chart for Torque. Higher is better · Nm / lb-ft

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
450 Nm
332 lb-ft
BMW6 Series Convertible (F12)640i
450 Nm
332 lb-ft

Curb weight comparison

Bar comparison chart for Curb weight. Lower is better · kg / lb

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
1,695 kg
3,737 lb
BMW6 Series Convertible (F12)640i
1,910 kg
4,211 lb

Top speed without limiter comparison

Bar comparison chart for Top speed without limiter. Higher is better · km/h / mph

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
BMW6 Series Convertible (F12)640i
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph

0-100 km/h comparison

Bar comparison chart for 0-100 km/h. Lower is better · seconds

Chart data table
VehicleValue
BMW6 Series (E63)645Ci5.8 s
BMW6 Series Convertible (F12)640i5.4 s

Although BMW 6 Series (E63) 645Ci has more power, BMW 6 Series Convertible (F12) 640i is quicker from 0-100 km/h.

The biggest 0-100 km/h difference is between BMW 6 Series Convertible (F12) 640i and BMW 6 Series (E63) 645Ci: 0.4 s.

Fuel consumption comparison

Bar comparison chart for Fuel consumption. Lower is better · L/100 km / mpg US / mpg UK

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
BMW6 Series Convertible (F12)640i
8.4 L/100 km
28.0 mpg US
33.6 mpg UK

The biggest fuel consumption difference is between BMW 6 Series Convertible (F12) 640i and BMW 6 Series (E63) 645Ci: 2.5 L/100 km.

Power-to-weight comparison

Bar comparison chart for Power-to-weight. Higher is better · hp/t / kW/t

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
196 hp/t
147 kW/t
5.1 kg/hp
BMW6 Series Convertible (F12)640i
168 hp/t
125 kW/t
6.0 kg/hp

Estimated range comparison

Bar comparison chart for Estimated range. Higher is better · km / mi

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
642 km
399 mi
BMW6 Series Convertible (F12)640i
833 km
518 mi

Performance spider chart

Radar chart comparing normalized performance and fuel-consumption scores.

Chart data table
VehiclePowerAccelerationTop speed
BMW6 Series (E63)645Ci
333 hp
248 kW
5.8 s
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
BMW6 Series Convertible (F12)640i
320 hp
239 kW
5.4 s
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph

Most attractive quadrant

Scatter chart with performance score on the X axis and practicality score on the Y axis.

Chart data table
VehiclePerformance scorePracticality score
BMW6 Series (E63)645Ci
Power
333 hp
248 kW
0-100 km/h5.8 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
4 seats
Trunk
450 L
15.9 cu ft
Length
4,820 mm
189.8 in
Height
1,373 mm
54.1 in
BMW6 Series Convertible (F12)640i
Power
320 hp
239 kW
0-100 km/h5.4 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,894 mm
192.7 in
Height
1,365 mm
53.7 in

Performance vs fuel economy

Cars closer to the top-right corner combine stronger performance with better fuel economy scores.

Performance vs fuel economy data table
VehiclePerformance scoreFuel economy score
BMW6 Series (E63)645Ci
Power
333 hp
248 kW
0-100 km/h5.8 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
BMW6 Series Convertible (F12)640i
Power
320 hp
239 kW
0-100 km/h5.4 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
8.4 L/100 km
28.0 mpg US
33.6 mpg UK

BMW 6 Series Convertible (F12) 640i is closest to the top-right balance target for performance and fuel economy.

Acceleration vs fuel consumption

Cars closer to the lower-left corner offer a better mix of quick acceleration and low fuel consumption.

Acceleration vs fuel consumption data table
VehicleFuel consumption, L/100 km0-100 km/h, s
BMW6 Series (E63)645Ci
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
5.8 s
BMW6 Series Convertible (F12)640i
8.4 L/100 km
28.0 mpg US
33.6 mpg UK
5.4 s

Power-to-weight vs fuel consumption

The shaded area favors higher power-to-weight with lower combined fuel consumption.

Power-to-weight vs fuel consumption data table
VehiclePower-to-weight, hp/tFuel consumption, L/100 km
BMW6 Series (E63)645Ci
196 hp/t
147 kW/t
5.1 kg/hp
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
BMW6 Series Convertible (F12)640i
168 hp/t
125 kW/t
6.0 kg/hp
8.4 L/100 km
28.0 mpg US
33.6 mpg UK

Detailed score breakdown

Detailed score breakdown
VehicleBMW6 Series (E63)645CiBMW6 Series Convertible (F12)640i
Power
333 hp
248 kW
320 hp
239 kW
Torque
450 Nm
332 lb-ft
450 Nm
332 lb-ft
Acceleration
5.8 s
5.4 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Lightness
1,695 kg
3,737 lb
1,910 kg
4,211 lb
Fuel consumption
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
8.4 L/100 km
28.0 mpg US
33.6 mpg UK
Practicality
Doors/seats
2 doors
4 seats
Trunk
450 L
15.9 cu ft
Length
4,820 mm
189.8 in
Height
1,373 mm
54.1 in
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,894 mm
192.7 in
Height
1,365 mm
53.7 in
Range score
642 km
399 mi
833 km
518 mi
CO2 score
264 g/km
195 g/km
Trunk score
450 L
15.9 cu ft
300 L
10.6 cu ft
Power-to-weight score
196 hp/t
147 kW/t
5.1 kg/hp
168 hp/t
125 kW/t
6.0 kg/hp
Overall
Fixed score
Fixed score

Fuel cost and annual usage

Estimate running costs from combined consumption, your annual distance, and the fuel price in your local currency.

Enter the fuel price in your local currency, for example €/L, $/gal, £/L or any other local currency.

LC = Local Currency

Fuel cost and annual usage
VehicleBMW 6 Series (E63) 645CiBMW 6 Series Convertible (F12) 640i
Consumption10.9 L/100 km21.6 mpg US25.9 mpg UK8.4 L/100 km28 mpg US33.6 mpg UK
Cost / 100 km19.08 LC100 km14.70 LC100 km
Cost / 100 mi30.70 LC100 mi23.66 LC100 mi
Annual fuel used1,635 L432 US gal360 UK gal1,260 L333 US gal277 UK gal
Annual fuel cost2,861 LC/year2,205 LC/year

Head-to-head comparisons

BMW 6 Series (E63) 645Ci

  • Has 13 hp more
  • Is 215 kg lighter
  • Has 5 km/h (3 mph) higher top speed
  • Has 29 hp/t better power-to-weight
  • Has 150 L more trunk volume

Pros

  • Highest top speed
  • Most powerful
  • Highest torque
  • Lightest
  • Best power-to-weight ratio
  • Largest trunk

Cons

  • Slowest 0-100 km/h
  • Highest combined fuel consumption
  • Highest CO2 emissions

BMW 6 Series Convertible (F12) 640i

  • Is 0.4 s quicker from 0-100 km/h
  • Uses 2.5 L/100 km less fuel
  • Has 191 km (119 mi) more estimated range
  • Emits 69 g/km less CO2

Pros

  • Quickest 0-100 km/h in this comparison
  • Lowest combined fuel consumption
  • Best estimated range

Cons

  • Lowest power
  • Heaviest
  • Lowest top speed
  • Smallest trunk

Choose cars to compare

Brand
Model
Generation
Engine or modification
BMW 6 Series (E63) 645Ci
BMW 6 Series Convertible (F12) 640i
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2 vehicles selected

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BMW 6 Series (E63) 645Ci vs BMW 6 Series Convertible (F12) 640i - car comparison - FastVsFaster