Car comparison

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

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)

420i

170 hp1597 ccGasolineRWDAutomaticTurbochargedCoupe2021-2024

Comparison overview

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

Best choices

BMW 4 Series Convertible (G23) 420i

  • Quickest 0-100 km/h
    8.2 s
  • Fastest top speed
    236 km/h
    147 mph
  • Most powerful
    184 hp
    137 kW
  • Highest torque
    300 Nm
    221 lb-ft
  • Best power-to-weight
    109 hp/t
    81 kW/t
    9.2 kg/hp
  • Lowest combined fuel consumption
    6.1 L/100 km
    38.6 mpg US
    46.3 mpg UK
  • Lowest city consumption
    7.4 L/100 km
    31.8 mpg US
    38.2 mpg UK
  • Lowest highway consumption
    5.4 L/100 km
    43.6 mpg US
    52.3 mpg UK
  • Best estimated range
    967 km
    601 mi
  • Best performance score
    48/100
  • Best economy score
    90/100

Specification comparison

Specification comparison
ModelBMW4 Series Convertible (G23)420iBMW4 Series Gran Coupe (G26)420i
Power
184hp137kW
170hp127kW
Torque
300Nm221lb-ft
250Nm184lb-ft
Curb weight
1,690kg3,726lb
1,620kg3,571lb
Gross weight
2,185kg4,817lb
2,175kg4,795lb
Top speed
236 km/h
147 mph
227 km/h
141 mph
To 99% top speed
107.5s99% target: 234 km/h / 145 mph
Calculated
105.0s99% target: 225 km/h / 140 mph
Calculated
0-100 km/h
8.2s
8.6s
0-200 km/h
36.3s
Calculated
41.4s
Calculated
0-60 mph
7.8s
Calculated
8.1s
Calculated
Fuel consumption
6.1L/100 km38.6mpg US46.3mpg UK
8.1L/100 km29mpg US34.9mpg UK
Fuel consumption city
7.4L/100 km31.8mpg US38.2mpg UK
8L/100 km29.4mpg US35.3mpg UK
Fuel consumption highway
5.4L/100 km43.6mpg US52.3mpg UK
7L/100 km33.6mpg US40.4mpg UK
Quarter mile
15.9s
Calculated
16.2s
Calculated
Power-to-weight
109hp/t81kW/t49hp/1000 lb
Calculated
105hp/t78kW/t48hp/1000 lb
Calculated
Torque-to-weight
178Nm/t119lb-ft/ton
Calculated
154Nm/t103lb-ft/ton
Calculated
Estimated range
967km601mi
Calculated
728km453mi
Calculated
Displacement
1,998cc122cu in
1,597cc97cu 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
1,595mm63in
Rear track
1,611mm63in
1,623mm64in
Ground clearance
124mm5in
-
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) 420iPowerTorque
  • BMW 4 Series Convertible (G23) 420i: Power / Torque
  • BMW 4 Series Gran Coupe (G26) 420i: 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)420i5,000-5,500 rpm2,000-4,400 rpm5,750 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricBMW4 Series Convertible (G23)420iBMW4 Series Gran Coupe (G26)420i
Acceleration checkpoints
0-60 mph
0-97 km/h
7.8 s
8.1 s
0-100 km/h
0-62 mph
8.2 s
8.6 s
0-200 km/h
0-124 mph
36.3 s
41.4 s
Top speed
236 km/h
147 mph
227 km/h
141 mph
Drag race simulation
60 ft
18 m
2.6 s
2.6 s
330 ft
101 m
6.9 s
7.0 s
1/8 mile
201 m
10.4 s
10.6 s
1000 ft
305 m
13.4 s
13.6 s
1/4 mile
402 m
15.9 s
16.2 s
Trap speed
1/4 mile
402 m
145 km/h
90 mph
142 km/h
88 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)420i
170 hp
127 kW

BMW 4 Series Convertible (G23) 420i has 14 hp more than BMW 4 Series Gran Coupe (G26) 420i.

The biggest power difference is between BMW 4 Series Gran Coupe (G26) 420i and BMW 4 Series Convertible (G23) 420i: 14 hp (10 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)420i
250 Nm
184 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)420i
1,620 kg
3,571 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)420i
227 km/h
141 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)420i8.6 s

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

The biggest fuel consumption difference is between BMW 4 Series Convertible (G23) 420i and BMW 4 Series Gran Coupe (G26) 420i: 2.0 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
BMW4 Series Convertible (G23)420i
109 hp/t
81 kW/t
9.2 kg/hp
BMW4 Series Gran Coupe (G26)420i
105 hp/t
78 kW/t
9.5 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)420i
728 km
453 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)420i
170 hp
127 kW
8.6 s
227 km/h
141 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)420i
Power
170 hp
127 kW
0-100 km/h8.6 s
Top speed
227 km/h
141 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)420i
Power
170 hp
127 kW
0-100 km/h8.6 s
Top speed
227 km/h
141 mph
8.1 L/100 km
29.0 mpg US
34.9 mpg UK

BMW 4 Series Convertible (G23) 420i 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)420i
8.1 L/100 km
29.0 mpg US
34.9 mpg UK
8.6 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)420i
105 hp/t
78 kW/t
9.5 kg/hp
8.1 L/100 km
29.0 mpg US
34.9 mpg UK

Detailed score breakdown

Detailed score breakdown
VehicleBMW4 Series Convertible (G23)420iBMW4 Series Gran Coupe (G26)420i
Power
184 hp
137 kW
170 hp
127 kW
Torque
300 Nm
221 lb-ft
250 Nm
184 lb-ft
Acceleration
8.2 s
8.6 s
Top speed
236 km/h
147 mph
227 km/h
141 mph
Lightness
1,690 kg
3,726 lb
1,620 kg
3,571 lb
Fuel consumption
6.1 L/100 km
38.6 mpg US
46.3 mpg UK
8.1 L/100 km
29.0 mpg US
34.9 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
728 km
453 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
105 hp/t
78 kW/t
9.5 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 4 Series Convertible (G23) 420iBMW 4 Series Gran Coupe (G26) 420i
Consumption6.1 L/100 km38.6 mpg US46.3 mpg UK8.1 L/100 km29 mpg US34.9 mpg UK
Cost / 100 km10.67 LC100 km14.17 LC100 km
Cost / 100 mi17.18 LC100 mi22.81 LC100 mi
Annual fuel used915 L242 US gal201 UK gal1,215 L321 US gal267 UK gal
Annual fuel cost1,601 LC/year2,126 LC/year

Head-to-head comparisons

BMW 4 Series Convertible (G23) 420i

  • Has 14 hp more
  • Has 50 Nm more
  • Is 0.4 s quicker from 0-100 km/h
  • Has 9 km/h (6 mph) higher top speed
  • Uses 2.0 L/100 km less fuel
  • Has 4 hp/t better power-to-weight
  • Has 239 km (148 mi) more estimated range

Pros

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

Cons

  • Heaviest
  • Smallest trunk

BMW 4 Series Gran Coupe (G26) 420i

  • Is 70 kg lighter
  • Has 170 L more trunk volume

Pros

  • Lightest
  • Largest trunk

Cons

  • Slowest 0-100 km/h
  • Lowest power
  • Highest combined fuel consumption
  • 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) 420i
Compare selected cars
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