What's your date of birth?

English as a Second Language English Vocabulary, Grammar and Idioms
1

Which usage is correct?

   (a) What's your date of birth? OR
   (b) What's the date of your birth?

            Thanks..
2

(a) is the usual, standard form.

3

“Date of birth” is usually taken together, though the other way of putting the question cannot be treated as incorrect.

4

Thanks…