BMW 8 Series (G14) (2020) is 441 mm (17.36 inch) longer and 116 mm (4.57 inch) wider than Mercedes B-Class (2018).
Mercedes B-Class (2018) is 218 mm (8.58 inch) higher, 538 kg (1,186 lbs) lighter and has 136 liters (4.80 ft3) bigger cargo space than BMW 8 Series (G14) (2020).