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 ccGasolineRWDAutomaticNaturally 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
    5.8 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
    1,695 kg
    3,737 lb
  • Best power-to-weight
    196 hp/t
    147 kW/t
    5.1 kg/hp
  • Lowest combined fuel consumption
    10.9 L/100 km
    21.6 mpg US
    25.9 mpg UK
  • Lowest city consumption
    16.1 L/100 km
    14.6 mpg US
    17.5 mpg UK
  • Lowest highway consumption
    8.0 L/100 km
    29.4 mpg US
    35.3 mpg UK
  • Best estimated range
    642 km
    399 mi
  • Largest trunk
    450 L
  • Best overall score
    63/100
  • Best performance score
    68/100
  • Best economy score
    78/100
  • Best practicality score
    53/100

Specification comparison

Specification comparison
ModelBMW6 Series (E63)645CiBMW6 Series Convertible (E64)645Ci
Power
333hp248kW
333hp248kW
Torque
450Nm332lb-ft
450Nm332lb-ft
Curb weight
1,695kg3,737lb
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
79.6s99% target: 262 km/h / 163 mph
Calculated
87.8s99% target: 257 km/h / 160 mph
Calculated
0-100 km/h
5.8s
6.2s
0-200 km/h
20.3s
Calculated
22.8s
Calculated
0-60 mph
5.5s
Calculated
5.9s
Calculated
Fuel consumption
10.9L/100 km21.6mpg US25.9mpg UK
11.5L/100 km20.5mpg US24.6mpg UK
Fuel consumption city
16.1L/100 km14.6mpg US17.5mpg UK
16.8L/100 km14mpg US16.8mpg UK
Fuel consumption highway
8L/100 km29.4mpg US35.3mpg UK
8.5L/100 km27.7mpg US33.2mpg UK
Quarter mile
13.9s
Calculated
14.3s
Calculated
Power-to-weight
196hp/t147kW/t89hp/1000 lb
Calculated
183hp/t136kW/t83hp/1000 lb
Calculated
Torque-to-weight
265Nm/t178lb-ft/ton
Calculated
247Nm/t165lb-ft/ton
Calculated
Estimated range
642km399mi
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
264g/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
5.5 s
5.9 s
0-100 km/h
0-62 mph
5.8 s
6.2 s
0-200 km/h
0-124 mph
20.3 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
6.1 s
6.2 s
1/8 mile
201 m
9.1 s
9.3 s
1000 ft
305 m
11.7 s
12.0 s
1/4 mile
402 m
13.9 s
14.3 s
Trap speed
1/4 mile
402 m
169 km/h
105 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
1,695 kg
3,737 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)645Ci5.8 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: 0.4 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 (E64)645Ci
11.5 L/100 km
20.5 mpg US
24.6 mpg UK

The biggest fuel consumption difference is between BMW 6 Series (E63) 645Ci and BMW 6 Series Convertible (E64) 645Ci: 0.6 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 (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
642 km
399 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
5.8 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/h5.8 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 (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/h5.8 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 (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
10.9 L/100 km
21.6 mpg US
25.9 mpg UK
5.8 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
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 (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
5.8 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
1,695 kg
3,737 lb
1,820 kg
4,012 lb
Fuel consumption
10.9 L/100 km
21.6 mpg US
25.9 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
642 km
399 mi
609 km
378 mi
CO2 score
264 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
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
Consumption10.9 L/100 km21.6 mpg US25.9 mpg UK11.5 L/100 km20.5 mpg US24.6 mpg UK
Cost / 100 km19.08 LC100 km20.13 LC100 km
Cost / 100 mi30.70 LC100 mi32.39 LC100 mi
Annual fuel used1,635 L432 US gal360 UK gal1,725 L456 US gal379 UK gal
Annual fuel cost2,861 LC/year3,019 LC/year

Head-to-head comparisons

BMW 6 Series (E63) 645Ci

  • Is 125 kg lighter
  • Is 0.4 s quicker from 0-100 km/h
  • Has 5 km/h (3 mph) higher top speed
  • Uses 0.6 L/100 km less fuel
  • Has 13 hp/t better power-to-weight
  • Has 34 km (21 mi) more estimated range
  • Has 150 L more trunk volume

Pros

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

Choose cars to compare

Brand
Model
Generation
Engine or modification
BMW 6 Series (E63) 645Ci
BMW 6 Series Convertible (E64) 645Ci
Compare selected cars
2 vehicles selected

Popular comparisons

645Ci
650i
VS
BMW6 Series (E63)645CivsBMW6 Series (E63)Facelift 2007650i
645Ci
650i
VS
BMW6 Series Convertible (E64)645CivsBMW6 Series Convertible (E64)Facelift 2007650i
645Ci
640i
VS
BMW6 Series (E63)645CivsBMW6 Series Gran Coupe (F06)640i
645Ci
640i
VS
BMW6 Series Convertible (E64)645CivsBMW6 Series Convertible (F12)640i
645Ci
645Ci
VS
BMW6 Series (E63)645CivsBMW6 Series Convertible (E64)645Ci
645Ci
645Ci
VS
BMW6 Series Convertible (E64)645CivsBMW6 Series (E63)645Ci
645Ci
640i
VS
BMW6 Series (E63)645CivsBMW6 Series Coupe (F13)640i
645Ci
M 635CSi
VS
BMW6 Series (E63)645CivsBMW6 Series (E24)Facelift 1982M 635CSi
645Ci
M 635CSi
VS
BMW6 Series (E63)645CivsBMW6 Series (E24)Facelift 1987M 635CSi
645Ci
640i
VS
BMW6 Series Convertible (E64)645CivsBMW6 Series Gran Turismo (G32)640i
645Ci
635CSi
VS
BMW6 Series (E63)645CivsBMW6 Series (E24)635CSi
645Ci
3.2i 24V
VS
BMW6 Series Convertible (E64)645CivsBMWM3 Convertible (E46)3.2i 24V
BMW 6 Series (E63) 645Ci vs BMW 6 Series Convertible (E64) 645Ci - car comparison - FastVsFaster