Car comparison

BMW 4 Series Convertible (G23) 420ivsBMW 4 Series Gran Coupe (G26) 420d

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

New comparison

BMW 4 Series Convertible (G23)

420i

184 hp1998 ccGasolineRWDAutomaticTurbochargedCabriolet / convertible2020-2024
VS

BMW 4 Series Gran Coupe (G26)

420d

190 hp1995 ccDieselAWDAutomaticTurbochargedCoupe2021-2024

Comparison overview

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

Best choices

BMW 4 Series Gran Coupe (G26) 420d

  • Quickest 0-100 km/h
    7.6 s
  • Most powerful
    190 hp
    142 kW
  • Highest torque
    400 Nm
    295 lb-ft
  • Lowest combined fuel consumption
    5.7 L/100 km
    41.3 mpg US
    49.6 mpg UK
  • Best estimated range
    1,035 km
    643 mi
  • Largest trunk
    470 L
  • Best overall score
    57/100
  • Best performance score
    52/100
  • Best economy score
    91/100
  • Best practicality score
    69/100

Specification comparison

Specification comparison
ModelBMW4 Series Convertible (G23)420iBMW4 Series Gran Coupe (G26)420d
Power
184hp137kW
190hp142kW
Torque
300Nm221lb-ft
400Nm295lb-ft
Curb weight
1,690kg3,726lb
1,760kg3,880lb
Gross weight
2,185kg4,817lb
2,315kg5,104lb
Top speed
236 km/h
147 mph
233 km/h
145 mph
To 99% top speed
107.5s99% target: 234 km/h / 145 mph
Calculated
96.3s99% target: 231 km/h / 143 mph
Calculated
0-100 km/h
8.2s
7.6s
0-200 km/h
36.3s
Calculated
34.3s
Calculated
0-60 mph
7.8s
Calculated
7.2s
Calculated
Fuel consumption
6.1L/100 km38.6mpg US46.3mpg UK
5.7L/100 km41.3mpg US49.6mpg UK
Fuel consumption city
7.4L/100 km31.8mpg US38.2mpg UK
-
Fuel consumption highway
5.4L/100 km43.6mpg US52.3mpg UK
-
Quarter mile
15.9s
Calculated
15.5s
Calculated
Power-to-weight
109hp/t81kW/t49hp/1000 lb
Calculated
108hp/t81kW/t49hp/1000 lb
Calculated
Torque-to-weight
178Nm/t119lb-ft/ton
Calculated
227Nm/t152lb-ft/ton
Calculated
Estimated range
967km601mi
Calculated
1,035km643mi
Calculated
Displacement
1,998cc122cu in
1,995cc122cu in
Length
4,768mm188in
4,783mm188in
Width
1,852mm73in
1,852mm73in
Height
1,384mm54in
1,442mm57in
Wheelbase
2,851mm112in
2,856mm112in
Front track
1,575mm62in
1,597mm63in
Rear track
1,611mm63in
1,624mm64in
Ground clearance
124mm5in
140mm6in
Trunk volume
300L
470L
Max trunk volume
385L
1,290L
Doors
2
5
Seats
4
5
Fuel tank
59L
59L

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 4 Series Convertible (G23) 420iBMW 4 Series Gran Coupe (G26) 420dPowerTorque
  • BMW 4 Series Convertible (G23) 420i: Power / Torque
  • BMW 4 Series Gran Coupe (G26) 420d: Power / Torque
Dyno simulation data table
VehiclePeak power RPMPeak torque RPMMax engine speed
BMW4 Series Convertible (G23)420i5,000-6,500 rpm1,350-4,000 rpm6,750 rpm
BMW4 Series Gran Coupe (G26)420d4,000 rpm1,750-2,500 rpm4,250 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricBMW4 Series Convertible (G23)420iBMW4 Series Gran Coupe (G26)420d
Acceleration checkpoints
0-60 mph
0-97 km/h
7.8 s
7.2 s
0-100 km/h
0-62 mph
8.2 s
7.6 s
0-200 km/h
0-124 mph
36.3 s
34.3 s
Top speed
236 km/h
147 mph
233 km/h
145 mph
Drag race simulation
60 ft
18 m
2.6 s
2.5 s
330 ft
101 m
6.9 s
6.7 s
1/8 mile
201 m
10.4 s
10.1 s
1000 ft
305 m
13.4 s
13.0 s
1/4 mile
402 m
15.9 s
15.5 s
Trap speed
1/4 mile
402 m
145 km/h
90 mph
148 km/h
92 mph

Power comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420i
184 hp
137 kW
BMW4 Series Gran Coupe (G26)420d
190 hp
142 kW

BMW 4 Series Gran Coupe (G26) 420d has 6 hp more than BMW 4 Series Convertible (G23) 420i.

The biggest power difference is between BMW 4 Series Convertible (G23) 420i and BMW 4 Series Gran Coupe (G26) 420d: 6 hp (4 kW).

Torque comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420i
300 Nm
221 lb-ft
BMW4 Series Gran Coupe (G26)420d
400 Nm
295 lb-ft

Curb weight comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420i
1,690 kg
3,726 lb
BMW4 Series Gran Coupe (G26)420d
1,760 kg
3,880 lb

Top speed without limiter comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420i
236 km/h
147 mph
BMW4 Series Gran Coupe (G26)420d
233 km/h
145 mph

0-100 km/h comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420i8.2 s
BMW4 Series Gran Coupe (G26)420d7.6 s

The biggest 0-100 km/h difference is between BMW 4 Series Gran Coupe (G26) 420d and BMW 4 Series Convertible (G23) 420i: 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
BMW4 Series Convertible (G23)420i
6.1 L/100 km
38.6 mpg US
46.3 mpg UK
BMW4 Series Gran Coupe (G26)420d
5.7 L/100 km
41.3 mpg US
49.6 mpg UK

Power-to-weight comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420i
109 hp/t
81 kW/t
9.2 kg/hp
BMW4 Series Gran Coupe (G26)420d
108 hp/t
81 kW/t
9.3 kg/hp

Estimated range comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420i
967 km
601 mi
BMW4 Series Gran Coupe (G26)420d
1,035 km
643 mi

Performance spider chart

Radar chart comparing normalized performance and fuel-consumption scores.

Chart data table
VehiclePowerAccelerationTop speed
BMW4 Series Convertible (G23)420i
184 hp
137 kW
8.2 s
236 km/h
147 mph
BMW4 Series Gran Coupe (G26)420d
190 hp
142 kW
7.6 s
233 km/h
145 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
BMW4 Series Convertible (G23)420i
Power
184 hp
137 kW
0-100 km/h8.2 s
Top speed
236 km/h
147 mph
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,768 mm
187.7 in
Height
1,384 mm
54.5 in
BMW4 Series Gran Coupe (G26)420d
Power
190 hp
142 kW
0-100 km/h7.6 s
Top speed
233 km/h
145 mph
Doors/seats
5 doors
5 seats
Trunk
470 L
16.6 cu ft
Length
4,783 mm
188.3 in
Height
1,442 mm
56.8 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
BMW4 Series Convertible (G23)420i
Power
184 hp
137 kW
0-100 km/h8.2 s
Top speed
236 km/h
147 mph
6.1 L/100 km
38.6 mpg US
46.3 mpg UK
BMW4 Series Gran Coupe (G26)420d
Power
190 hp
142 kW
0-100 km/h7.6 s
Top speed
233 km/h
145 mph
5.7 L/100 km
41.3 mpg US
49.6 mpg UK

BMW 4 Series Gran Coupe (G26) 420d 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
BMW4 Series Convertible (G23)420i
6.1 L/100 km
38.6 mpg US
46.3 mpg UK
8.2 s
BMW4 Series Gran Coupe (G26)420d
5.7 L/100 km
41.3 mpg US
49.6 mpg UK
7.6 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
BMW4 Series Convertible (G23)420i
109 hp/t
81 kW/t
9.2 kg/hp
6.1 L/100 km
38.6 mpg US
46.3 mpg UK
BMW4 Series Gran Coupe (G26)420d
108 hp/t
81 kW/t
9.3 kg/hp
5.7 L/100 km
41.3 mpg US
49.6 mpg UK

Detailed score breakdown

Detailed score breakdown
VehicleBMW4 Series Convertible (G23)420iBMW4 Series Gran Coupe (G26)420d
Power
184 hp
137 kW
190 hp
142 kW
Torque
300 Nm
221 lb-ft
400 Nm
295 lb-ft
Acceleration
8.2 s
7.6 s
Top speed
236 km/h
147 mph
233 km/h
145 mph
Lightness
1,690 kg
3,726 lb
1,760 kg
3,880 lb
Fuel consumption
6.1 L/100 km
38.6 mpg US
46.3 mpg UK
5.7 L/100 km
41.3 mpg US
49.6 mpg UK
Practicality
Doors/seats
2 doors
4 seats
Trunk
300 L
10.6 cu ft
Length
4,768 mm
187.7 in
Height
1,384 mm
54.5 in
Doors/seats
5 doors
5 seats
Trunk
470 L
16.6 cu ft
Length
4,783 mm
188.3 in
Height
1,442 mm
56.8 in
Range score
967 km
601 mi
1,035 km
643 mi
Trunk score
300 L
10.6 cu ft
470 L
16.6 cu ft
Power-to-weight score
109 hp/t
81 kW/t
9.2 kg/hp
108 hp/t
81 kW/t
9.3 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 4 Series Convertible (G23) 420iBMW 4 Series Gran Coupe (G26) 420d
Consumption6.1 L/100 km38.6 mpg US46.3 mpg UK5.7 L/100 km41.3 mpg US49.6 mpg UK
Cost / 100 km10.67 LC100 km9.98 LC100 km
Cost / 100 mi17.18 LC100 mi16.05 LC100 mi
Annual fuel used915 L242 US gal201 UK gal855 L226 US gal188 UK gal
Annual fuel cost1,601 LC/year1,496 LC/year

Head-to-head comparisons

BMW 4 Series Convertible (G23) 420i

  • Is 70 kg lighter
  • Has 3 km/h (2 mph) higher top speed
  • Has 1 hp/t better power-to-weight

Pros

  • Highest top speed
  • Lightest
  • Best power-to-weight ratio

Cons

  • Slowest 0-100 km/h
  • Lowest power
  • Highest combined fuel consumption
  • Smallest trunk

BMW 4 Series Gran Coupe (G26) 420d

  • Has 6 hp more
  • Has 100 Nm more
  • Is 0.6 s quicker from 0-100 km/h
  • Uses 0.4 L/100 km less fuel
  • Has 68 km (42 mi) more estimated range
  • Has 170 L more trunk volume

Pros

  • Quickest 0-100 km/h in this comparison
  • Most powerful
  • Highest torque
  • Lowest combined fuel consumption
  • Best estimated range
  • Largest trunk

Cons

  • Heaviest
  • Lowest top speed

Choose cars to compare

Brand
Model
Generation
Engine or modification
BMW 4 Series Convertible (G23) 420i
BMW 4 Series Gran Coupe (G26) 420d
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2 vehicles selected

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