Car comparison

BMW 6 Series (E63) 645CivsBMW 6 Series Convertible (E64) 645Ci

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

New comparison

BMW 6 Series (E63)

645Ci

333 hp4398 ccGasolineRWDManualNaturally aspiratedCoupe2003-2005
VS

BMW 6 Series Convertible (E64)

645Ci

333 hp4398 ccGasolineRWDAutomaticNaturally aspiratedCabriolet / convertible2003-2005

Comparison overview

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

Best choices

BMW 6 Series (E63) 645Ci

  • Quickest 0-100 km/h
    5.6 s
  • 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
    1,690 kg
    3,726 lb
  • Best power-to-weight
    197 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 (E64) 645Ci

  • Lowest combined fuel consumption
    11.5 L/100 km
    20.5 mpg US
    24.6 mpg UK
  • Lowest city consumption
    16.8 L/100 km
    14.0 mpg US
    16.8 mpg UK
  • Lowest highway consumption
    8.5 L/100 km
    27.7 mpg US
    33.2 mpg UK
  • Best estimated range
    609 km
    378 mi
  • Best economy score
    76/100

Specification comparison

Specification comparison
ModelBMW6 Series (E63)645CiBMW6 Series Convertible (E64)645Ci
Power
333hp248kW
333hp248kW
Torque
450Nm332lb-ft
450Nm332lb-ft
Curb weight
1,690kg3,726lb
1,820kg4,012lb
Gross weight
2,065kg4,553lb
2,220kg4,894lb
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
76.8s99% target: 262 km/h / 163 mph
Calculated
87.8s99% target: 257 km/h / 160 mph
Calculated
0-100 km/h
5.6s
6.2s
0-200 km/h
19.6s
Calculated
22.8s
Calculated
0-60 mph
5.3s
Calculated
5.9s
Calculated
Fuel consumption
11.7L/100 km20.1mpg US24.1mpg UK
11.5L/100 km20.5mpg US24.6mpg UK
Fuel consumption city
17.2L/100 km13.7mpg US16.4mpg UK
16.8L/100 km14mpg US16.8mpg UK
Fuel consumption highway
8.6L/100 km27.4mpg US32.8mpg UK
8.5L/100 km27.7mpg US33.2mpg UK
Quarter mile
13.7s
Calculated
14.3s
Calculated
Power-to-weight
197hp/t147kW/t89hp/1000 lb
Calculated
183hp/t136kW/t83hp/1000 lb
Calculated
Torque-to-weight
266Nm/t178lb-ft/ton
Calculated
247Nm/t165lb-ft/ton
Calculated
Estimated range
598km372mi
Calculated
609km378mi
Calculated
Displacement
4,398cc268cu in
4,398cc268cu in
Length
4,820mm190in
4,820mm190in
Width
1,855mm73in
1,855mm73in
Height
1,373mm54in
1,373mm54in
Wheelbase
2,780mm109in
2,780mm109in
Front track
1,558mm61in
1,558mm61in
Rear track
1,592mm63in
1,592mm63in
Trunk volume
450L
300L
Max trunk volume-
350L
Doors
2
2
Seats
4
4
Fuel tank
70L
70L
CO2 emissions
283g/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 (E64) 645CiPowerTorque
  • BMW 6 Series (E63) 645Ci: Power / Torque
  • BMW 6 Series Convertible (E64) 645Ci: 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 (E64)645Ci6,100 rpm3,600 rpm6,350 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricBMW6 Series (E63)645CiBMW6 Series Convertible (E64)645Ci
Acceleration checkpoints
0-60 mph
0-97 km/h
5.3 s
5.9 s
0-100 km/h
0-62 mph
5.6 s
6.2 s
0-200 km/h
0-124 mph
19.6 s
22.8 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
2.4 s
330 ft
101 m
6.0 s
6.2 s
1/8 mile
201 m
9.0 s
9.3 s
1000 ft
305 m
11.6 s
12.0 s
1/4 mile
402 m
13.7 s
14.3 s
Trap speed
1/4 mile
402 m
170 km/h
106 mph
163 km/h
101 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 (E64)645Ci
333 hp
248 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 (E64)645Ci
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
1,690 kg
3,726 lb
BMW6 Series Convertible (E64)645Ci
1,820 kg
4,012 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 (E64)645Ci
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)645Ci5.6 s
BMW6 Series Convertible (E64)645Ci6.2 s

The biggest 0-100 km/h difference is between BMW 6 Series (E63) 645Ci and BMW 6 Series Convertible (E64) 645Ci: 0.6 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
11.7 L/100 km
20.1 mpg US
24.1 mpg UK
BMW6 Series Convertible (E64)645Ci
11.5 L/100 km
20.5 mpg US
24.6 mpg UK

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
197 hp/t
147 kW/t
5.1 kg/hp
BMW6 Series Convertible (E64)645Ci
183 hp/t
136 kW/t
5.5 kg/hp

Estimated range comparison

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

Chart data table
VehicleValue
BMW6 Series (E63)645Ci
598 km
372 mi
BMW6 Series Convertible (E64)645Ci
609 km
378 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
5.6 s
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
BMW6 Series Convertible (E64)645Ci
333 hp
248 kW
6.2 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/h5.6 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 (E64)645Ci
Power
333 hp
248 kW
0-100 km/h6.2 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
4,820 mm
189.8 in
Height
1,373 mm
54.1 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/h5.6 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
11.7 L/100 km
20.1 mpg US
24.1 mpg UK
BMW6 Series Convertible (E64)645Ci
Power
333 hp
248 kW
0-100 km/h6.2 s
Top speed
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
11.5 L/100 km
20.5 mpg US
24.6 mpg UK

BMW 6 Series (E63) 645Ci 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
11.7 L/100 km
20.1 mpg US
24.1 mpg UK
5.6 s
BMW6 Series Convertible (E64)645Ci
11.5 L/100 km
20.5 mpg US
24.6 mpg UK
6.2 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
197 hp/t
147 kW/t
5.1 kg/hp
11.7 L/100 km
20.1 mpg US
24.1 mpg UK
BMW6 Series Convertible (E64)645Ci
183 hp/t
136 kW/t
5.5 kg/hp
11.5 L/100 km
20.5 mpg US
24.6 mpg UK

Detailed score breakdown

Detailed score breakdown
VehicleBMW6 Series (E63)645CiBMW6 Series Convertible (E64)645Ci
Power
333 hp
248 kW
333 hp
248 kW
Torque
450 Nm
332 lb-ft
450 Nm
332 lb-ft
Acceleration
5.6 s
6.2 s
Top speed
Unrestricted
265 km/h165 mph
Restricted
250 km/h155 mph
Unrestricted
260 km/h162 mph
Restricted
250 km/h155 mph
Lightness
1,690 kg
3,726 lb
1,820 kg
4,012 lb
Fuel consumption
11.7 L/100 km
20.1 mpg US
24.1 mpg UK
11.5 L/100 km
20.5 mpg US
24.6 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
4,820 mm
189.8 in
Height
1,373 mm
54.1 in
Range score
598 km
372 mi
609 km
378 mi
CO2 score
283 g/km
-
Trunk score
450 L
15.9 cu ft
300 L
10.6 cu ft
Power-to-weight score
197 hp/t
147 kW/t
5.1 kg/hp
183 hp/t
136 kW/t
5.5 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 (E64) 645Ci
Consumption11.7 L/100 km20.1 mpg US24.1 mpg UK11.5 L/100 km20.5 mpg US24.6 mpg UK
Cost / 100 km20.47 LC100 km20.13 LC100 km
Cost / 100 mi32.95 LC100 mi32.39 LC100 mi
Annual fuel used1,755 L464 US gal386 UK gal1,725 L456 US gal379 UK gal
Annual fuel cost3,071 LC/year3,019 LC/year

Head-to-head comparisons

BMW 6 Series (E63) 645Ci

  • Is 130 kg lighter
  • Is 0.6 s quicker from 0-100 km/h
  • Has 5 km/h (3 mph) higher top speed
  • Has 14 hp/t better power-to-weight
  • Has 150 L more trunk volume

Pros

  • Quickest 0-100 km/h in this comparison
  • Highest top speed
  • Most powerful
  • Highest torque
  • Lightest
  • Best power-to-weight ratio
  • Largest trunk

Cons

  • Highest combined fuel consumption

BMW 6 Series Convertible (E64) 645Ci

  • Uses 0.2 L/100 km less fuel
  • Has 10 km (6 mi) more estimated range

Pros

  • Lowest combined fuel consumption
  • Best estimated range

Cons

  • Slowest 0-100 km/h
  • 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 (E64) 645Ci
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