Car comparison

BMW 4 Series Convertible (G23) 420dvsBMW X3 (G45) 20

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

New comparison

BMW 4 Series Convertible (G23)

420d

190 hp1995 ccDieselRWDAutomaticTurbochargedCabriolet / convertible2020-2024
VS

BMW X3 (G45)

20

190 hp1597 ccGasolineRWDAutomaticTurbocharged2025-present

Comparison overview

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

Best choices

BMW 4 Series Convertible (G23) 420d

  • Quickest 0-100 km/h
    7.6 s
  • Fastest top speed
    236 km/h
    147 mph
  • Most powerful
    190 hp
    142 kW
  • Highest torque
    400 Nm
    295 lb-ft
  • Lightest
    1,775 kg
    3,913 lb
  • Best power-to-weight
    107 hp/t
    80 kW/t
    9.3 kg/hp
  • Lowest combined fuel consumption
    4.5 L/100 km
    52.3 mpg US
    62.8 mpg UK
  • Best estimated range
    1,311 km
    815 mi
  • Best performance score
    52/100
  • Best economy score
    95/100

BMW X3 (G45) 20

  • Largest trunk
    570 L
  • Best overall score
    56/100
  • Best practicality score
    78/100

Specification comparison

Specification comparison
ModelBMW4 Series Convertible (G23)420dBMWX3 (G45)20
Power
190hp142kW
190hp142kW
Torque
400Nm295lb-ft
310Nm229lb-ft
Curb weight
1,775kg3,913lb
1,780kg3,924lb
Gross weight
2,270kg5,004lb
2,425kg5,346lb
Top speed
236 km/h
147 mph
218 km/h
135 mph
To 99% top speed
99.0s99% target: 234 km/h / 145 mph
Calculated
103.0s99% target: 216 km/h / 134 mph
Calculated
0-100 km/h
7.6s
8.4s
0-200 km/h
33.5s
Calculated
48.1s
Calculated
0-60 mph
7.2s
Calculated
7.9s
Calculated
Fuel consumption
4.5L/100 km52.3mpg US62.8mpg UK
8.2L/100 km28.7mpg US34.4mpg UK
Fuel consumption city
5L/100 km47mpg US56.5mpg UK
-
Fuel consumption highway
4.3L/100 km54.7mpg US65.7mpg UK
-
Quarter mile
15.5s
Calculated
16.1s
Calculated
Power-to-weight
107hp/t80kW/t49hp/1000 lb
Calculated
107hp/t80kW/t48hp/1000 lb
Calculated
Torque-to-weight
225Nm/t151lb-ft/ton
Calculated
174Nm/t117lb-ft/ton
Calculated
Estimated range
1,311km815mi
Calculated
793km493mi
Calculated
Displacement
1,995cc122cu in
1,597cc97cu in
Length
4,768mm188in
4,755mm187in
Width
1,852mm73in
1,920mm76in
Height
1,384mm54in
1,660mm65in
Wheelbase
2,851mm112in
2,865mm113in
Front track
1,575mm62in
1,636mm64in
Rear track
1,611mm63in
1,681mm66in
Ground clearance
124mm5in
216mm9in
Trunk volume
300L
570L
Max trunk volume
385L
1,700L
Doors
2
5
Seats
4
5
Fuel tank
59L
65L

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) 420dBMW X3 (G45) 20PowerTorque
  • BMW 4 Series Convertible (G23) 420d: Power / Torque
  • BMW X3 (G45) 20: Power / Torque
Dyno simulation data table
VehiclePeak power RPMPeak torque RPMMax engine speed
BMW4 Series Convertible (G23)420d4,000 rpm1,750-2,500 rpm4,250 rpm
BMWX3 (G45)204,400-6,500 rpm2,200-4,000 rpm6,750 rpm

Acceleration curve

Estimated speed over time for selected vehicles.

Acceleration and drag-race table
MetricBMW4 Series Convertible (G23)420dBMWX3 (G45)20
Acceleration checkpoints
0-60 mph
0-97 km/h
7.2 s
7.9 s
0-100 km/h
0-62 mph
7.6 s
8.4 s
0-200 km/h
0-124 mph
33.5 s
48.1 s
Top speed
236 km/h
147 mph
218 km/h
135 mph
Drag race simulation
60 ft
18 m
2.5 s
2.5 s
330 ft
101 m
6.7 s
6.8 s
1/8 mile
201 m
10.1 s
10.4 s
1000 ft
305 m
13.0 s
13.5 s
1/4 mile
402 m
15.5 s
16.1 s
Trap speed
1/4 mile
402 m
149 km/h
92 mph
141 km/h
87 mph

Power comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
190 hp
142 kW
BMWX3 (G45)20
190 hp
142 kW

Torque comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
400 Nm
295 lb-ft
BMWX3 (G45)20
310 Nm
229 lb-ft

Curb weight comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
1,775 kg
3,913 lb
BMWX3 (G45)20
1,780 kg
3,924 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)420d
236 km/h
147 mph
BMWX3 (G45)20
218 km/h
135 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)420d7.6 s
BMWX3 (G45)208.4 s

The biggest 0-100 km/h difference is between BMW 4 Series Convertible (G23) 420d and BMW X3 (G45) 20: 0.8 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)420d
4.5 L/100 km
52.3 mpg US
62.8 mpg UK
BMWX3 (G45)20
8.2 L/100 km
28.7 mpg US
34.4 mpg UK

The biggest fuel consumption difference is between BMW 4 Series Convertible (G23) 420d and BMW X3 (G45) 20: 3.7 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)420d
107 hp/t
80 kW/t
9.3 kg/hp
BMWX3 (G45)20
107 hp/t
80 kW/t
9.4 kg/hp

Estimated range comparison

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

Chart data table
VehicleValue
BMW4 Series Convertible (G23)420d
1,311 km
815 mi
BMWX3 (G45)20
793 km
493 mi

Performance spider chart

Radar chart comparing normalized performance and fuel-consumption scores.

Chart data table
VehiclePowerAccelerationTop speed
BMW4 Series Convertible (G23)420d
190 hp
142 kW
7.6 s
236 km/h
147 mph
BMWX3 (G45)20
190 hp
142 kW
8.4 s
218 km/h
135 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)420d
Power
190 hp
142 kW
0-100 km/h7.6 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
BMWX3 (G45)20
Power
190 hp
142 kW
0-100 km/h8.4 s
Top speed
218 km/h
135 mph
Doors/seats
5 doors
5 seats
Trunk
570 L
20.1 cu ft
Length
4,755 mm
187.2 in
Height
1,660 mm
65.4 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)420d
Power
190 hp
142 kW
0-100 km/h7.6 s
Top speed
236 km/h
147 mph
4.5 L/100 km
52.3 mpg US
62.8 mpg UK
BMWX3 (G45)20
Power
190 hp
142 kW
0-100 km/h8.4 s
Top speed
218 km/h
135 mph
8.2 L/100 km
28.7 mpg US
34.4 mpg UK

BMW 4 Series Convertible (G23) 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)420d
4.5 L/100 km
52.3 mpg US
62.8 mpg UK
7.6 s
BMWX3 (G45)20
8.2 L/100 km
28.7 mpg US
34.4 mpg UK
8.4 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
BMW4 Series Convertible (G23)420d
107 hp/t
80 kW/t
9.3 kg/hp
4.5 L/100 km
52.3 mpg US
62.8 mpg UK
BMWX3 (G45)20
107 hp/t
80 kW/t
9.4 kg/hp
8.2 L/100 km
28.7 mpg US
34.4 mpg UK

Detailed score breakdown

Detailed score breakdown
VehicleBMW4 Series Convertible (G23)420dBMWX3 (G45)20
Power
190 hp
142 kW
190 hp
142 kW
Torque
400 Nm
295 lb-ft
310 Nm
229 lb-ft
Acceleration
7.6 s
8.4 s
Top speed
236 km/h
147 mph
218 km/h
135 mph
Lightness
1,775 kg
3,913 lb
1,780 kg
3,924 lb
Fuel consumption
4.5 L/100 km
52.3 mpg US
62.8 mpg UK
8.2 L/100 km
28.7 mpg US
34.4 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
570 L
20.1 cu ft
Length
4,755 mm
187.2 in
Height
1,660 mm
65.4 in
Range score
1,311 km
815 mi
793 km
493 mi
Trunk score
300 L
10.6 cu ft
570 L
20.1 cu ft
Power-to-weight score
107 hp/t
80 kW/t
9.3 kg/hp
107 hp/t
80 kW/t
9.4 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) 420dBMW X3 (G45) 20
Consumption4.5 L/100 km52.3 mpg US62.8 mpg UK8.2 L/100 km28.7 mpg US34.4 mpg UK
Cost / 100 km7.88 LC100 km14.35 LC100 km
Cost / 100 mi12.67 LC100 mi23.09 LC100 mi
Annual fuel used675 L178 US gal148 UK gal1,230 L325 US gal271 UK gal
Annual fuel cost1,181 LC/year2,153 LC/year

Head-to-head comparisons

BMW 4 Series Convertible (G23) 420d

  • Has 90 Nm more
  • Is 5 kg lighter
  • Is 0.8 s quicker from 0-100 km/h
  • Has 18 km/h (11 mph) higher top speed
  • Uses 3.7 L/100 km less fuel
  • Has 0 hp/t better power-to-weight
  • Has 518 km (322 mi) more estimated range

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

Cons

  • Smallest trunk

BMW X3 (G45) 20

  • Has 270 L more trunk volume

Pros

  • Largest trunk

Cons

  • Slowest 0-100 km/h
  • Highest combined fuel consumption
  • Heaviest
  • Lowest top speed

Choose cars to compare

Brand
Model
Generation
Engine or modification
BMW 4 Series Convertible (G23) 420d
BMW X3 (G45) 20
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