How does the motoring industry define vehicle classes in terms of size?

We regularly read at the launch of a new car ‘largest in class’. Am I being cynical or is the car simply not the smallest in the class above? Does the motor industry have standards for this or is this just marketing spin?

Asked on 21 March 2011 by SW, Cockermouth

Answered by Honest John
A is small: Hyundai i10, Ford Ka, Citroen C1, etc. B is a bit bigger: Hyundai i20, Ford Fiesta, Citroen C3, etc. C is mid-size: Hyundai i30, Ford Focus, Citroen C4, etc. D is family-size: Hyundai i40, Ford Mondeo, Citroen C5, etc.
Similar questions
I am looking to trade in my 2003 Seat Leon Tdi and am in the market for a used mid / large sized family car. My commute equates to around 300 miles a week and we also travel longer distances at weekends...
I am changing my car shortly and would like to know which small to medium-size family cars are not fitted with low profile tyres.
Have an old Audi Avant. I'm looking for a newer (12 months old perhaps) medium sized saloon/hatch. I want to avoid DSG gearboxes and electronic/ pedal handbrakes. I also want a car that has good visibility...