Tintin & Friends: How old are they?

Tintin is clearly 15 or older, as he was seen driving a car in The Blue Lotus (p.52, panel 15.)

Why just 15?

Between pages 9 and 11 of Soviets he steals both a motor-cycle and side-car and a motor-car and crashes them both, and he flies a stolen 'plane on p.112 (crashes it on p.113) - so all we really know is he likes to steal modes of transport and wreck them...
I am sure you have some reason to pick 15 as Tintin's age, but as he seems to have a flexible attitude to the law, I don't think you can assume that he waited for driving to be legal.

Do you mean it is legal to drive at 15 in China?

Well let's see here... Assuming he was intended by Hergé to be around 20 or so (Tintin is never very "kiddish"), then I figure by the time he was roaming the jungles of San Theodoros with Haddock and Alcazar, he must have been around 67... :)

I thought he was 75
Rik

Nice one, Rik!
Jyrki21, I think when Tintin starts out in Soviets he is definitely a boy reporter - perhaps even a child.
There isn't any logic to it, but then the narrative isn't realistic.
I suppose he is meant to be someone with whom the readers of Le Petit Vingtième could identify.
The prototypes of Tintin, such as Tintin-Lutin and Totor, are all youngsters, and I think it transfers across. His feet don't even touch the floor when he sits on the seat in the train.

I think he starts off as a boy reporter, but I would say that by the time of America and Broken Ear he has become a reporter in his twenties, an age which he then maintains for the rest of the series.
If I had to pick an age specifically, I would go for a baby-faced 26/27.

As an aside, how old is Haddock?
I would say a decade older, certainly less than 40, while Calculus is in his mid- to late-40s.

I'd put the "regular" Tintin at 18-20, 22 tops, Captain Haddock between 45 and 55, and Calculus in his sixties.

Well I always thought 20's to be honest, and I'd say Calculus was in his 40's tops. Captain Haddock around the same age as well

Rik

I'd put Tintin 15-25, Haddock 50 and Calculus in his mid-60s.