How do you write Date of birth words?

There are a few ways to write "Date of birth" in words:

Formal:

* Date of birth

* Birth date

Informal:

* DOB (abbreviation)

* Birthday (often used in the context of asking for someone's birthdate)

Other variations:

* Born on

* Date born

* Day of birth

The best option depends on the context and formality of the situation.