C'est quand ton anniversaire? or Quand est ton anniversaire?
I saw this sentence in my book: "C'est quand ton anniversaire?"
But I didn't see this sentence: "Quand est ton anniversaire?" Is this sentence wrong?

Question

C'est quand ton anniversaire? or Quand est ton anniversaire?
I saw this sentence in my book: "C'est quand ton anniversaire?" 
But I didn't see this sentence: "Quand est ton anniversaire?" Is this sentence wrong?

Answer

Je pense n'avoir jamais entendu quiconque dire "quand est ton anniversaire".

"C'est quand, ton anniversaire" est le plus courant, et dans un registre différent, on a "quand c'est, ton anniversaire".

Sinon "quand est-ce que c'est ton anniversaire" n'est pas mal non plus. Ou bien "ton anniversaire c'est quand ? "

Le mieux est de dire "tu es né quel jour".

Answer

Noth are corrects but it's more common to say "c'est quand ton anniversaire ?"

Answer

That is a good question. The short answer is : no one says, and you will never hear « Quand est ton anniversaire ? », therefore, you should not use it, period.

But indeed, this is a very good question, and a tricky one. Because you surely can say « Où est ton livre ? » I'd love to say that I have the answer, but I don't. So far.  ;)
I hope I'll come back with it soon.

Answer

No ^^ you can say both

Answer

Hi !
"C'est quand ton anniversaire?" is the most used of those both sentences but any is wrong.