BMW 5 Series (2018) is 550 mm (21.65 inch) longer, 81 mm (3.19 inch) wider and has 83 liters (2.93 ft3) bigger cargo space than Mercedes B-Class (2014).
Mercedes B-Class (2014) is 58 mm (2.28 inch) higher and 320 kg (705 lbs) lighter than BMW 5 Series (2018).